So, this mainly happens in a folder i have named "incoming" in my documents. This is where I store files from Bittorrent or other p2p files as they come in. It usually happens when I am browsing the files and I will click on a file, not even to open it, but just single click it, and the folder will freeze and stop responding. The only way I can get out of it is to force close it with cntrl alt delete. It sometimes does it with other folders as well, but I have not noticed happen as much. Somtimes it doesn't do it and the computer runs fine, but it seems to happen quite a bit lately.
I am running a rig I biult myself with a p4 2.5, 1gig RAM, radeon 8500