Question : How do I prevent Blue Screen most likely being caused by nvidia Drivers?

Started getting the Blue Screen of Death (XP PRo) a few weeks ago.  The frequency has increased to 2 or 3 times a day.  Each time, the identifying culprit seems to be different (ie,  ndis.sys,  ksecdd.sys,  fltmgr.sys, etc).  It seems to be nvidia related.  I've tried uninstalling and reinstalling the nvidia software & drivers ...  but nothing seems to repair the problem.  Should I being working with the registry? One other item .... occasionally one of my screens is blotchy in the top third of the screen.  Looks like it lost a portion of the video .. sorta like when the satellite TV dish loses it's signal.   I'm stuck ... this is my office pc ... I have backed it up but I really don;t want to configure a new pc.  Any advice before I throw it out the window?  (Dell Optiplex Gx280 with e-GeForce 8600 GTS Graphics Card installed - dual monitor)

Answer : How do I prevent Blue Screen most likely being caused by nvidia Drivers?

Fixed ... the problem was the RAM chip in Slot 1.!  I don;t know if the video card triggered it .... but everything has been running without the BSOD for 2 days.  PS.  I have NOT reinstalled the GeForce 8600 GTS Graphics Card .. but I will next week.