Video problems?

I have a Ti4600, I all of a sudden am having problems with.. I tried to
upgrade my system memory and it messed up my video? ( who knows? ) anyway
ever since then I took out new memory, but on my ( what seems to be so far )
OpenGL games. I have problems with them. At first I thought it was only
Medal of Honor. I am playin' then my video starts flashing ( for lack of a
more correct term) like its almost switching video modes? not with the
monitor clicking too, but I can still see the game ( kinda ) not well enough
to play at all.. I re-installed newest video drivers and it worked again
fine, then did it again.. reinstalled drivers it worked for a day again (
all the web pages seem to work fine, and everything else ) but then today I
tried playing Quake2.. just cause.. I was messin' around, and it started to
do it in Quake now too.. turn off quake, and I get good video. I tried
to get on quake again and it was flashing still.. so I installed the box
drivers that came with card.. old ones. It seems to be working again ( for
now ?? ) This is why I assume its an openGL problem?? I use DX8 not 9.0.. I
tend to think its not the video card going bad 1 because its only 2 months
old, and 2 because my windows seems to work fine. only the OpenGL games so
far are messing up.

Has this happend to anyone else??
is it a Drivers problem??
would DX9 help?
or is it common probblem for a video card thats going south?? ;(
is there a known fix for this?? if its drivers, ( cause its just happening
on openGL ) I thought DX9 might help but I just hate to download it cause b4
everything was working perfect. I had NO problems till I tried to add
memory, so maybe its corrupt drivers, but when I re-installed them the first
time it should have fixed it???