View Full Version : Computer question - only sometimes turns on...

2005-04-28, 06:47 AM
For the last two months or so my computer only sometimes turns on and when it does it's after on average about 20 minutes of it just sitting there making the noise of the fans, et running.

When the power is turned on but the computer doesn't start up the keyboard seems to work (the 'Num Lock' button works, etc), the CD and DVD drives work, and there's power to the speakers, but the computer doesn't want to boot up and get going.

Can anybody please tell me what's wrong with it? Is there a part that I can replace to get it working again? Last night I left it trying for about 12 hours and it didn't turn on...I think it's getting worse.

Thanks a lot,

2005-04-28, 07:33 AM
A failing power supply can cause problems like that. If the power supply isn't supplying a stable voltage to the CPU or other component then the computer can misbehave (fail to boot, crash randomly, etc.).

There are utilities that can measure and graph the various voltages from the power supply. You can watch the graph and check to see if some of the voltages are drifting out of spec.

Intel has a monitor utility for their chipsets: Intel Active Monitor (http://intel.com/design/motherbd/active.htm). If you have a chipset or motherboard that it supports it should be able to monitor the power supply.

Motherboard Monitor 5 (http://mbm.livewiredev.com/) is another monitoring program. I haven't used it so I don't know well it monitors or graphs the power supply voltages.

Some BIOSes have a screen that will display the CPU temperature and power supply voltages. Boot to your BIOS and see what it will tell you.

There are lots of other free monitoring programs that will let you monitor the power supply voltages.

2005-04-28, 08:12 AM
my old 98se PC did that..i think it was combo of it being old and full of nastys. it would come on just long enough to get me thinking i was ok,then it would crash.

i never figured out what it was, fortunatly i was given a newer box (to me) PC with Win 2000 and it works all the time and never crashes.

2005-04-28, 08:26 AM
Thanks. If I can get it to turn on again I'll try out one of those programs. Is there a big range in types of power supplies? Is there a right on to get or will any do?

The computer doesn't crash but it does choose to restart itself if it is left running without any activity for too long.

Another unrelated computer question...
It currently doesn't shut itself down all the way when I tell it to but instead goes to the "It is now safe to turn off your computer" screen. I find this annoying. Is there an easy way with Windows XP to make it shut down all the way?


2005-04-28, 08:35 AM
there might be some useful info about power supplys in my old PC thread.


EDIT: i fixed my Psupp with a dbl. shot of WD-40 on the fan.

2005-04-28, 08:44 AM
Just don't turn it off. All problems solved.

2005-04-28, 11:56 AM
Originally posted by andrew_carter
Another unrelated computer question...
It currently doesn't shut itself down all the way when I tell it to but instead goes to the "It is now safe to turn off your computer" screen. I find this annoying. Is there an easy way with Windows XP to make it shut down all the way?
This may be more of an indication of a power supply problem as John said. Old power supplies used to be switched by the switch on the PC case (AT power supply) but now the power supply is switched by the motherboard and the switch on the case is connected to the motherboard (ATX power supply). Using ACPI (Advanced Configuration and Power Interface) software (i.e. Windows) can turn the computer off. A problem with the power supply or with ACPI will often cause Windows to bring up the "It is now safe to turn off your computer" screen you see as it cannot turn the power supply off.

Power supplies are easy to change and if you can borrow a known good one it would be a quick way to check and it's always prudent to check that all cables etc. are seated well when you have a PC open.

Also ACPI can usually be turned on or off in the BIOS.

Does that lot make sense? I work in ICT so I ramble a bit :)

2005-04-28, 02:00 PM
Before changing any parts, I would open the case and re-seat all the boards and connectors. Make sure everything is tight and you don't have any loose connections on any wires or circuit boards. This is easy enough to do and does not cost anything. Sometimes when machines get old, the connectors get a little bit corroded which interupts the connection.

Power supplies come in different sizes. Make sure you have the right one before you change it.

2005-04-28, 02:08 PM
It's probably the power supply because that's what our old PC was doing and that's what ended up being the problem.

2005-04-28, 04:33 PM
Originally posted by TheObieOne3226
Just don't turn it off. All problems solved.

now, theres an idea!

The Yang
2005-04-28, 04:34 PM
I never turn mine off, I have a feeling it doesn't have a lot of boot ups left

2005-04-28, 04:51 PM
only sometimes turns on...

My wife has the same problem.

2005-04-28, 07:18 PM
Originally posted by pdc
My wife has the same problem.

2005-04-28, 09:40 PM
Thanks a lot guys. :) That's definitely all the info I need for now. I'll have a look at it this afternoon. Hopefully I'll get back from uni before the shops close.


2005-04-28, 11:40 PM
Maybe you need to get better at foreplay?

(y'know, only sometimes turns on?)


ok, sorry.

2005-04-29, 01:09 AM

You should retaliate! If it only turns on part of the time then you should only turn it off part of the time. That'll show it.

You're a lege, mate.


2005-04-29, 01:33 PM
Originally posted by harper

You should retaliate! If it only turns on part of the time then you should only turn it off part of the time. That'll show it.

You're a lege, mate.


Interesting logic...?

2005-05-06, 12:39 PM
Finally, after three days of trying, I've managed to turn the computer on. I pull the hard drive and power supplies out and blew on them so I'm going to say in my infinite knowledge of computers that that's what convinced it to start working again. ;) Well actually, it's not working all that well. It's horribly slow and I still have the original problem of it only turing on sometimes. I'm about to download one of the programs you linked to John.

I'm thinking maybe my hard drive needs replacing as well/instead. The computer is obviously running now, and it's very slow and the hard drive is making funny noises. Also, about every second attempt at turning it on it will tell me on that really basic looking black screen with white text (the BIOS?) that there is no Primary Master drive...in which case I reset and it usually finds it the second time around.

So does this sound like a hard drive problem to you?

My brother is going to try to find me a free 20GB hard drive second hand from a friend which is nice because I have no money to be spending on computers...that money is for my muni frame! :)

It seems to have out-smarted me and figured out how to turn itself off without my permission. :)


2005-05-06, 07:56 PM
Get the power supply checked first. It could be the root of the problem. If the power supply is going bad the BIOS could be getting reset to default settings. The BIOS being reset to default settings could result in the computer running slower. It could also result in the hard drive needing to be rediscovered and then running in a slower access mode.

Changing a power supply is fairly straightforward for a computer repair. The main issue is getting the right connectors connected to the MB and components. Then routing the mass of cables so they look good and don't restrict air flow in the case and stay out of the way of the fans. Then cable tie them to keep them bundled up and in place.

Take some pictures of what connector is connected where and how the wires are routed. A video picture that you can display on the TV would be good. Then refer to those pictures when putting it all back together.

Then once you get the power supply fixed you'll need to go in the BIOS and change things from the default settings to where they should be to get the computer back up to speed. You may need some advice from experienced people to determine what settings to use for memory access and the hard drive.

The power supply that comes stock in most computers is really bare minimum in terms of quality. The manufacturers don't splurge on a good power supply because that adds cost with no immediate benefit (the benefit comes when they don't fail later on, but by that time the computer is sold and it's in your hands not theirs).