|Thanks for the hint - a little bit ago I finished the last of the scans I wanted to try.|
I powered the computer down last night and restarted it this morning. I noticed that the taskbar hung on a second longer than usual, but if I hadn't been watching for it I wouldn't have noticed. There did not seem to be any issues at startup.
When the error occurred, I was searching on the external, running Winamp, and looking at something in Firefox.
After it happened and a little before shutdown, I tried doing a search for music in a folder on the harddrive and had no issues.
Today I have run an SFC scan - it is set to use my I386 folder if it needs to fix something, it did not give me any popups or anything so I think it came back all right. I have also run an Avira, Malwarebytes AntiMalware, and SuperAntiSpyware scan, as well as an error check on the C drive. All have come up clean.