PC constantly re-booting

Hi. I have a problem with my PC constantly re-booting for no apparent reason. I know for sure it is the machine not working properly, and it's got nothing to do with windows, because it reboots also when Linux is loaded, or it may reboot while loading the system. The thing is that, in order to start switching off and on again (and off and on...) you need to use it for a while (after leaving it switched off for some time), and for about a week (or two) gives you no problem at all. At a certain stage it simply decides to quit, goes down and reboots. It's not an overheating problem either 'cause I've checked, and the RAM too was checked and everything seems to be in perfect conditions. But even when it's working, it's quite slow when I compare it to my other PC - which (in theory) shouldn't be as fast, and its components (cpu + motherboard) almost the very same!...

CPU: Pentium D 920 (2.8ghz)
MOBO: Asus p5b se
RAM: 1x4gb 800mhz
GRAPHIC CARD: hd2400 (512mb ram)
HD: 2 (320 + 300 gb)​

Hope you can help.

Thanks.

 

You could try the following:

1. Right-Click on My Computer, and choose Properties.
   
2. In the System Properties window, click on the Advanced tab.
   
3. Locate the Startup and Recovery area and click on the Settings button.
   
4. In the Startup and Recovery window, locate and uncheck the check box next to Automatically restart.
   
5. Click OK in the Startup and Recovery window.
   
6. Click OK in the System Properties window.

Now when there's a problem, it won't reboot. Instead it will show a blue screen with an error message. When you see that message, you can post that here so we can find the cause of the problem.

 

Ok. Thanks. I never thought of that.

 

Sorry but the trick doesn't work. The machine failure totally overrides the OS and reboots anyway - without warning or blue screens.

It's got to be the motherboard!...

 

Well actually, a sudden power loss could indicate a problem with the power supply. I'd suggest to try a different power supply, if possible. Read this thread for more information about Power Supplies.

 

If this is the problem, the original Power Supply Unit broke and was replaced with a more powerful model. So the actual one is a new 600Watt model. Two technicians saw the PC and said that nothing seems wrong with the machine. One said that the reason for it constantly re-booting was the dual-boot, which sounds incredibly strange to me that it could be the cause.