After installing my RADEON X800 drivers I get an "Uknown Device" (Location: on RADEON X800 series), on the device manager. I used Windows Update dor the first updates and then the recent Video Drivers from the ATI drivers website. I believe this is causing the computer to auto-reboot everytime I try to run a video file (after a minute or so running) or watch a video online (like youtube). Sometimes I get the "Unknown Device" to disappear but the problem precists.
Does this card have VIVO (video in video out) or is it an AIW? Do you have a brand and model or part number for the card? If it's a VIVO card the "unknown device" is probably the Rage Theater chip.
EDIT - My guess is that you have a VIVO version of the card as the AIW would have an antenna jack and would show several devices in the "other devices" category. One way to tell is to look on the back of the card and see if there is a largish chip that says "Rage Theater" on it. If so you may need a different set of drivers.
I have the exact same problem! I installed the X800 XL card just now. No it's not an AIW. My device manager looks EXACTLY like the screen shots provided by srd. Same details under "display adapters", same unknown device, same thing that it says in the properties.
Oh, I got it fixed. Thanks for the replies anyway. It's a stupid but simple screw-up on ATI's part. What was needed was to install two sets of software, each one a different download from ATI's website. One of them claims to be the complete suite, but in reality it's not complete -- it's missing the WDM drivers. (Despite the fact that the description says it has them.) I tried downloading and running the only other download they had posted, named "WDM Integrated Driver," and that was the magic bullet.