Damn, this sucks, another one.

I too had Win 7 without SP1 on there.

I'm wondering, were you also running RDP or VNC services? VNC for example could've been cracked if you had an easy to guess password.

Try running a bunch of online virus scaners like bitdefender, f-secure online scan, eset online scan, panda activescan...

Run spybot, malwarebytes..and last but not least combofix in case you may have a rootkit. Either way dude I strongly recommend you format, reinstall get yourself a legit copy of Win 7 if you don't already have it and update to SP1. Also if you are inclined to learn a bit about linux setup a dedicated linux box to store your bitcoins on. At the very least run a Linux install in Vmware or something.