Inspiron 1545 Video Drivers and GM45 Express Chipset

I have a Dell Inspiron 1545 with an Intel GM45 Express Chipset.  I am running Windows Vista Home Basic with 4 meg of ram.  On boot up I get the message "Display driver stopped responding and has recovered, Display driver igfx stopped responding and has successfully recovered"  This happens periodically throughout the session.  I have narrowed this issue down to the chipset drivers by using device manager and have tried updating the drivers on several occasions with no success.  I tried upgrading to Windows 7 and this only made the problem worse (lockups).  Currently I have done a clean install and used the drivers and OS software that originally came with the unit (July 2009) but the problem persists.  Anybody have any ideas??