Please, go to folder \windows\minidump and send the newest (recent) .mdmp files for analysis.
There is also C:\Windows\Memory.dmp file.
Better if you can compress (zip), rename it with an unique name, them and add some information about the BSOD and the link for this thread. 
Upload it to this anonymous ftp server: ftp://ftp.avast.com/incoming/
Disable Automatic Restart:
System Properties > Advanced > [Startup and Recovery]Settings
Remove the checkmark from “Automatically Restart” in the System Failure section.
Besides Google also you can use:
MS knowledgebase: http://support.microsoft.com/search/?adv=1
Free memory tester (Run it overnight): http://www.memtest86.com/
XP error explanations: http://www.xptuneup.com/xptuneup_stopmessages.htm
BSODs: http://www.techmetica.com/howto/descriptions-and-fixes-of-blue-screen-of-death-bsod-crash-errors/
Manual dump: when the machine is in stalled state, hold down the rightmost CTRL key, and press the SCROLL LOCK key twice. This will cause a machine to ‘blue-screen’ and dump of memory will start.
More info: http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=71
To generate full dump instead of only kernel (or small dump), see http://www.msfn.org/board/creating-memory-dumps-t130005.html.