New video card problems?

hi all just bought a His radeon Ati 256mb ddr dvi tv agp-8x 9550 video card and im having nothing but problems with it.My pc is an acer aspire T135 with on board all in one crap card 80gb hd and 756 ram i have the install disc and loaded a driver off that but dont seem to be able to find any newer ones on the net.Anyway long story short is i try to play a game any game using this new vid card and you play for about a minute then the screen keeps flashing off and on which ive realised each time it does this its lowering all settings [display resolution,hardware exeleration etc]to it gets to a point where the game is unplayable because all the direct draw and 3d is turned off by about the 3rd refresh if you need anymore info please ask and i will edit this post straight away with info if i can thanks in advance|||Power supply or cooling?|||Did you go into the BIOS and set the graphic card to the ATI?|||The HIS 9550 is a slow budget card (4 pixel pipelines/250mhz core/400mhz v-ram.

You are probably trying to play at high resolution and high quality game settings that is why the card is resetting to get better frame rates.

Try setting in game options the lowest quality. Start at low display resolution. Try 16bit color quality instead of 32bit.