Random reboots + minidump included

My problem first started a few weeks ago , would randomly reboot , mainly in games , i just upgraded video card , so im already pretty certain that was the problem , now tonight my computer started getting pissy and kept rebooting every time id start up windows etc etc. well . Like i said , im pretty sure it was ATI drivers because i put my old video card back in (nvidia) and booted right up , all is well, Well here are some minidumps , would appreciate it if ya could check em out n get back to me with some sort of solution or the root of the problem, Thanks.
first three are from tonight , and the last one is from a few days ago , for comparison because that was when it was rebooting whilst in a game.
Ryan

Inside the 4 Minidumps

BugCheck 1000008E, {c0000005, bf825595, b8aa9c54, 0}
Probably caused by : hardware ( win32k!MNFreeItem+2d )

BugCheck A, {1e0d37e, 2, 0, 804e11d2}
Probably caused by : NDIS.sys ( NDIS!ndisGlobalLock+3 )

BugCheck A, {0, 2, 1, 804e138e}
Probably caused by : ntoskrnl.exe ( nt!KeWaitForMutexObject+ec )

BugCheck 1000008E, {c000001d, e36c3780, b805388c, 0}
Probably caused by : ati3duag.dll ( ati3duag+11a5c8 )

Click to expand...

Please run Memtest on your Ram
And confirm all your Manufacture drivers are up to date

Also EQgame (one of the crashes referred to) confirm in option.exe (should be in the EQ program folder) that the screen is set to 800x600

Alright, Apreciate your time , i knew it was the ATI ! No sense in running memtest or anything , i changed back to nvidia card and my pc booted and stopped bsod... Im going to work on finding a solution to this problem , i discovered a post from a while back about someone having that same "ati3duag.dll" problem in everquest, his specs were almost identical to mine also , can check out that thread i just replyed on it. Seems that he fixed his game problem by using driver cleaner, and installing some "omega ati drivers" dunno but its worth a shot, i believe the recent problem starting windows was due to that "ati3duag.dll" problem but that happened in lord of the rings online , funny thing was system froze and did not blue screen that time , so it caused all sorts of chaos....