I'm not sure, but.. Did you try to hook up another external drive? If you did, did your computer see it as J: or as K: drive?
How about drive space? You have enough free space for system restore? (about 12% for large drives) I know system restore looks for available space at C: drive, but it also creates restore points for (and on) each drive on your putter by default. It doesn't really matter if they are separate drives, external drives or drives that you created on separate partitions.
On other hand, I have LaCie external drive and time ago for some reason he switched himself off and was invisible to system. After power up everything was fine. So maybe you can try to power on/off external disk instead of unplugging usb cable.
Edited by Notorious, 03 February 2009 - 12:41 PM.
Down in the bayou, Bubba called an attorney and asked, "Is it true they're suin' the cigarette companies for causing people to get cancer?
"Sure is Bubba. But why you asking?"
"Cause what I want to know is, I was thinking, can I sue Budweiser for all them ugly women I've slept with?"