Tried it last night. I shut down bitcoin and then moved all but wallet.dat to another folder. I started bitcoin back up and it connected and I left it run for an hour, no changes. This morning when I turned my computer on bitcoin says: Error loading blkindex.dat
This makes me think your antivirus is messing with blkindex.dat.
If you're using the most recent version of Bitcoin, try running it with the -rescan switch.