Help! Video blinks on and off

[Darn]

600 MHz Duron on MSI K7T PRO 2-A with ATI Xpert 98 running windows 98SE. The PC was built in Jan. of this year and ran flawlessly till a couple of weeks ago ( it would run completely stable for weeks at a time without rebooting). Started having trouble with random freezes, performance slowing down, and the video blinking on and off.
No hardware or software changes since initial setup except for virus definition updates and such. Bootup started taking an extended length of time and when booting or when the system would freeze the HD activity light would burn continually.
I ran benchmarks and tests on cpu (OK), memory(OK), and HD(lockup) the HD is a Maxtor 20GB 7200 RPM ATA 100. I downloaded the diagnostic tools from Maxtor and ran on the HD but it would not finish any of the tests so I replaced the HD and reloaded Windows and all drivers. The system ran fine for about 48 hours then problems started again.
I'm thinking maybe video card but I do not have one available to try and wanted to get a second opinion before buying a replacement.:disgust:
This is my mothers computer and about all they do with it is play card games on it so it is not like they are really stressing the components or overclocking the DARN thing.

 

[spanky]

if u think its the video card, why don't u stick another card in there and see if that eases anything. otherwise, those crashes could really be from anything. u just gotta plug in different parts and test them.
my first guess would be the memory. also, r u overclocking the cpu?

 

[Darn]

Thanks for the reply.
I will have another good stick of RAM I can try so I will give that a shot.