I have a tower PC, with XP home. When I power it up it goes through the start process, it gets to the windows screen with the blue loading bar, the lights on the modem come on then after 10 or so seconds the power goes off, then comes on again and goes through this cycle over and over again never getting any further then this. When I turn the machine off the light on the key board stays on as does the light on the card reader slots although there or no cards in any of the slots. Any advice would be grateful received as my wife is getting quite perplexed with me.

How are you powering off the PC, just by hitting the power button? If so, try holding the button in for at least 5 seconds to completely power off the PC. If that does not work, try unplugging the PC for 30 seconds and plugging it back in and powering it on. If it is still going through the power cycleing, it may be an OS issue where a driver is corrupt (or other file) causing windows to blue screen (BSoD) where it flashes so fast on the screen that either your monitor doesn't display it or you can't see it - (there is a setting in Windows that disables the PC from restarting immediately after this type of error but since you can't get into windows, it may not be possible).

Also try this:
When you start your PC, after it shows the POST (testing memory, detects drives etc etc) immediately press the F8 key. This should bring up a menu that gives you several choices - 'Start Normally' - 'Safe Mode' - 'Safe Mode with Networking' - 'Safe Mode with Command prompt' etc etc. Once you get this menu, boot to 'Safe Mode' and see if it will at least load Windows in Safe Mode. If it does, thenyou probably have a corrupt driver or corrupt file loading at startup.

Report back with your findings.

This post has been edited by Decepticon: Jun 30 2008, 08:57 AM

Hi Decepticon, It now turns off competely but wont start windows still. I tried what you suggested ( Safe Mode, then -your last normal setting- then normal start mode - none of them made any difference it still does the same thing. What next? is it terminal???

Hello tomwunder,

It sounds like a Power Supply issue.
Do you have another Power Supply you can try?
Or maybe a friend that can let you borrow his to check this.

I would've let you run a program to check the PSU (Power Supply Unit) but since it's in a booting loop we can't do that
Also, what is the Beep code you receive when you start up the computer?
The beep code is supposed to be 1 short beep. This indicates the computer booted normally.

Regards,
Olrik

Yeah, I would say it's a PSU issue as well. Are all the fans running when you start the PC up? Check your CPU fan as well, as it could be overheating very quickly as well. But, it sounds like it's more like a PSU issue.