Grats on getting up and running. I've hardy ever been successful uninstalling and reinstalling different ATI drivers, most of the time I get the same application error if I do that. Since these are mining machines, it doesn't take long for a reinstall (Win7 64-bit SP1 installed from USB stick, no updates or anything else). I disable windows update and the rest of the action messages, install system drivers, a few utilities (VNC, Winzip, Afterburner, .net 4.0), then install the ATI drivers depending on card (6x gets 11.11, 7x gets 13.4, 7790 gets the custom one), copy my base cgminer and go.
The reinstall saves a lot of frustration. A 450w PSU is enough to drive a single card, anything above that you may be running into power issues.
I only have a single card. I didn't have any luck with XP, and it looks like it just flat out won't work with XP, so I gave up on any uninstallers, and did a Windows 7 install, and everything worked out of the box. The install didn't take long for me, since I just ran it off the Active Directory server here at my work. It's currently running in a company machine, while I figure out the settings and order a license key for my own rig at home, to run it off of.
I tried the settings that were posted above, but going for a full 900mhz and 1300mhz RAM. instantly caused a reboot (not sure if it was a bluescreen, or not, because I was running it over Google Remote Desktop. I will play around with settings some this morning. Forgot to bring the PSU with me. I'm only running one card.
I was able to run the RAM up to about 1280, but it was unstable and caused the driver to crash. It SEEMED stable at 1233mhz RAM and 898 Engine, @1.1v, but automatic updates rebooted the machine about 45 min. after I went to bed last night, so I have no idea if it would have run stabile or not. More testing throughout the day today. The difference between 1280 RAM and 1233 is only about 1.5khash, so definitely not worth pushing it much harder than it is, if it will run solid with these settings. There also doesn't seem to be much difference in performance in going from 20 Intensity down to 19, except that it too may have contributed to the driver failure when it was at the full 20. Hard to say without more long-term testing.
Thanks again for the help, you guys! I may give Linux another shot at home, before I drop $200 on a Windows 7 license.
EDIT: Well, crap. It ran for about an hour and a half and the driver crashed, and CGMiner declared the card "sick" but kept running it while very slowly dropping hashing speed. I gave it 10 minutes, and it never fully stopped, or restarted, so I restarted it manually.
Is this a driver issue? Any idea what might be causing this?