Vista - Constant Crashing In Games

In the last week or so my computer has been restarting itself without warning whilst playing video games.

When I reboot I get this notice:
"A problem caused windows to stop working correctly. Windows will notify you if there is a solution."

System specs if you need them:

AMD 64 X2 6000+@3.01ghz
3.07Gb Ram
Sapphire 3850 256mb version
(Can't Remember Mobo)

Plz help me if you can.

Follow these easy steps to disable the automatic restart feature for system failures in Windows Vista.
Difficulty: Easy
Time Required: Disabling the Automatic Restart option in Windows Vista usually takes less than 10 minutes
Here's How:

1. Click on Start and then Control Panel.
   Tip: In a hurry? Type system in the search box after clicking Start. Choose System from the list of results and then skip to Step 4.
2. Click on the System and Maintenance link.
   Note: If you're viewing the Classic View of Control Panel, you won't see this link. Simply double-click on the System icon and proceed to Step 4.
3. Click on the System link.
4. In the task pane on the left, click the Advanced system settings link.
5. Locate the Startup and Recovery area and click on the Settings button.
6. In the Startup and Recovery window, locate and uncheck the check box next to Automatically restart.
7. Click OK in the Startup and Recovery window.
8. Click OK in the System Properties window.
9. You can now close the System window.
10. From now on, when a problem causes a BSOD or another major error that halts the system, the PC will not automatically reboot. Rebooting manually will be necessary.

STEP 4

The final step is to check your RAM and Hard drive to make sure they are working properly. First you should check you RAM for errors by clicking the vista start orb and typing in the search bar MdSched then hit enter then click on restart now.

You can now check your hard drive for errors by clicking on the vista start orb and then clicking on Computer. You then right click on your hard drive and click Properties. Next go to the Tools tab and under Error Checking click on Check Now and tick both the boxes. Then click Start and reboot your pc.