Well... First, disabling pagefile will almost a always give you more problems than not, if you can... check your pagefile, make sure it's on and not too small. Second, you might want to try memtest, test your memory for errors, do at least 5 passes. Another note, check your drivers
, make sure they're the latest (go to the product manufacturer's website to get the latest driver
, don't use windows update).
Edit: Another note: check event viewer for any critical errors...