PC hanged automatically

I'm now using Windows vista. Recently i found out that my PC automatically hang after turning on a while without giving any warning signal. It just hang and did not give any response. The only thing i can do is manually switch off the computer and restart it. When it was restarting, the computer will prompt me to start windows as safe mode or normally.

Does anyone encounter this problem before? What can I do or check to rectify this problem? It is very irritating when I haven't save my project when it got hanged and I have to re-do all my things again. Is it a hardware, virus or spyware problem?

 

If you have nvidia drivers, it can be worth rolling back the driver as these have given problems in the past.
Also there are some stability updates that Microsoft has , that do not get updated with other updates, that might help.
http://support.microsoft.com/kb/kb938979
http://support.microsoft.com/kb/kb938194
http://support.microsoft.com/kb/kb941600
http://support.microsoft.com/kb/kb941649

 

Have you got a little popup on the start bar, showing problem, I am not in Vista at the moment, but I remember a little warning box in the startbar, when I was working on them a while ago.
Look in Control panel-view problem history to see if anything shows up, in applications, or, drivers.
Have you used a usb stik, that you might have had problems with- couldnot find driver for it?- I did get a problem in Vista with one brand of usb stik.

 

I don't see any mini icon on the taskbar. It just hanged when i start my computer after a while.

 

That pop up comes up briefly when computer starts, and once clicks, seems tonot come back.
Go to start
Control panel
Swithch to classic view, and click on problems and solutions
You then have choices i the left column
and in the main panel, in front of you, problems found , on lower part, and solutions in top of panel- if any.

 

Also while in classic view
Click on performance information and tools
On the next page , in the left column, click on advanced
In the advanced page, click on view performance details inevent viewer.
If you then double click on any error warning, or, yellow triangle, you will get a small box telling you what the error was- you can click to go-on line for help.

 

I tried to kill all application and turn on the PC for a day and it did not hang. However, when I try to on Windows live messenger, it hanged after a while. Does it related to my Windows live messenger? Or does it related to other program that i turn on, like Windows sidebar and stuff like that? Or does it related to my PC's ram?