I've been using my ATI Radeon 9600 SE (AGP) on Windows XP without any problems, except once I had a small problem when I tried to uninstall Radlinker, an overclocking utility for ATI video cards. I have been unable to uninstall Radlinker since then, but everything was going fine for a few months. Then suddenly I was unable to write to the registry, and when I restarted my computer explorer and many other programs wouldn't start (msconfig, cmd, and some others would though). I eventually used msconfig to start with nothing and enable everything one by one until explorer would start. I got it down to a service, and later found it to be "Shell Hardware Detection". Whether I started it (explorer doesn't start then) or I didn't (explorer starts, many things don't work... MSN Messenger, Windows Messenger, My Computer freezes explorer until I restart it). A "Found New Hardware" window always pops up whether I use my 9600SE, onboard video, or my NVidia MX 4000. The MX 4000 seems the most promising because I can actually get drivers to think they're installing instead of just leaving the device driverless. However, after installing the MX 4000 drivers, it (Found New Hardware window) gives me the error message: "An error occured during the installation of the device. The parameter is incorrect." Starting Shell Hardware Detection when Windows is already started also freezes explorer and makes it unable to restart. Programs I installed recently incude File Association Editor, WAssociate, and Unlocker. I installed the first two because a few weeks ago I lost the ability to edit file associations through the normal "Tools > Folder Options > File Types tab" way (this was before I completely lost all ability to edit the registry). I have only one user on my computer and I am an administrator. I made sure I had permissions to edit the registry, but I still get the error: "Cannot create value: Error writing to the registry." Firefox, explorer (as long as I don't go to My Computer), and some programs run normally. So now I'm left with a 50% functional Windows XP which has extremely bad video (scrolling on web pages is extremely jerky and slow) no matter what I use for video (9600SE, MX 4000, or onboard). Can someone please give me any advice on what I could try before I reinstall Windows? I forgot to mention I had used my MX 4000 and the drivers were stable for about a year before I upgraded to my 9600SE, and also that all my System Restore points prior to the catastrophe (yesterday morning) somehow got deleted. Thank you for your help.
Edit: I forgot to say I uninstalled my 9600SE drivers after the registry mess-up and before I figured out Shell Hardware Detection was the problem and I was unable to reinstall them because ATI's installer said I should use generic VGA drivers before trying to install the drivers, and I couldn't get it to work when I followed M$'s instructions on how to do that.
Edit: I forgot to say I uninstalled my 9600SE drivers after the registry mess-up and before I figured out Shell Hardware Detection was the problem and I was unable to reinstall them because ATI's installer said I should use generic VGA drivers before trying to install the drivers, and I couldn't get it to work when I followed M$'s instructions on how to do that.