use a cleaning tool for uninstaling the video driver( it must be deleted from registers), or after uninstaling, go to regedit and delete it(Start>run>regedit, if u don't nkow) . Try with a new driver, a standard one.Hmm it's strange that thing with the mouse...
hmmm... you know what, screw those drivers given by ATI. Get the Omega drivers. They offer more utilities and probably may solve your problems. Latest Omega driver is based on the catalyst 6.1 driver. I think...
it's better if u change ur video card . 9250? Not good at all, try a 6600 (or gt) agp card. No problems with drivers, 99.99% compatibility. Why? Because nvidia has mature drivers, not like ati (i dont want to offense ati fans), they are not capable to make good drivers, and yes, u could try with omega drivers ( customized ati drivers),
Back in normal mode, the mouse was working properly; but after a few minutes the driver somehow re-installed itself.
That doesn't happen from the ATi side, if you do not have the appropriate driver M$ will automatically install it's default driver unless you tell it not to. These are never as good as the ATi and nV drivers, and afterwards can cause problems afterwards even when you install the proper drivers.
Also make sure your MoBo BIOS is up to date as VIA boards are very finicky with display drivers and graphics cards (best to turn of fastwrites IMO), I know from experience with mine and their forums.
If you are having difficulty you can try installing the 6.1 driver package instead of the one from the CD, although from the sound of things it's likely a MoBo issue (with 8x) which I've seen described a few times, but it could be a number of things.
I restarted and I got stuck at a black screen.
I restarted again; Windows (XP) successfully loaded, then after a few minutes the pc restarted on its own.
After the restart, a message appears saying that the driver seems to be responsible for the system instability.
That specifically sounds like an issue with fastwrites and the VIA boards are notorious for having issues with that. Updating the BIOS and the MOBO AGP drivers often helps, but disabling Fastwrites is always a good idea when experiencing instability on VIA boards.
So I tried to uninstall it again but again, after a few minutes, it re-installed itself once more.
ATi doesn't re-install drivers, Microsoft does, and you want to cancel that, as they only F'up the works for the MFR's drivers.
I believe ATi drivers have problems on most video cards too, but this is clearly an issue with the motherboard chipset/AGP drivers. Update chipset drivers (for intel) or AGP drivers (for amd or VIA/SIS based intel chipset).
Hmm more nV bugs in the current and archived list.
Considering M$'s statements on compatability I'd say they also disagree with you, so I'm not alone in thinking you're blowing smoke or smokin' something bad.
Both ATi and nV have their issues, although most of the times issue like this are poorly troubleshot, and then exacerbated by DumbA$$es like yourself offering their Fanboi take on things telling them to spend more money on hardware they don't need.