cant install iiyama drivers after switching gfx card  

I've got an iiyama vision master pro 454 monitor and today i changed graphics card today from a radeon 4850 to a radeon 5770 but after doing it my monitor drivers seem to have reset to generic pnp monitor instead of iiyama ones. I've tried downloading the iiyama drivers but even when i point it at the drivers it tells me my driver is up to date and doesnt change. Strange since windows automatically found the right drivers for me when i installed it.
Any ideas how i might get it to work?

If the windows default work, why would want to change them?

well the windows default doesnt give me many resolutions and limits me to a refresh rate of 85. I found if i do Have disk then point it at the driver from the download it says the drivers arent designed to work with the display and perhaps i should make sure they are 64bit drivers... got em off the iiyama site.

Look for x64 otherwise 7 drivers are all that will work.

how come it worked before then.. automatically at that!

found this thread Vista Refresh Rate / Iiyama HM903DT - Page 2 - nV News Forums but it didnt really fix the problem, i mean it does now say its using the iiyama driver but i dont have all the resolutions/refresh rates... although if i go into quakelive i can run at at 1600x1200 at 100hz. If i go on world of warcraft i can have 1600x1200 but am limited to 75hz. Bizzare, and a bit annoying

You can try modifying the resolution with Powerstrip:

EnTech Taiwan | Utilities | PowerStrip

looks good. thanks i'll give it a whirl