This is a common complaint for AGP cards but your post lacks details.
Some how i been unable to install new driver for my power colour hd5770. they latest one i able to install is 10.3. somehow newer driver never work. even when i go to check install log. it say everthying is fine. but when i reboot after installation. it say driver may not installed properly. i even when as far as reinstalling my window 7 32 to wipe all file. but still doesnt work.
here a few thing i notice.
the 10.3 is call 10-3_vista32_win7_32_dd_ccc_wdm_enu
while anything newer is called 10-7_vista32_win7_32_dd_ccc_enu notice no wdm
also when i install 10.3. it flicker to low resolution back to high resolution. while newer drvier flicker to low resolution and stay at low resolution.
i am runing window 7 32bit. can anyone tell me what wrong? and how to install newer driver?