If you are on a LAN, you many also want to keep a lookout for this problem on other PCs. Klez spreads via network shares.
I had a user recieve this via e-mail and she opened it.
There was a problem with her pc reaching the antivirus server so the defs. were not up to date and it wasn't caught right then.
As soon as it tried to spread over the network, I caught it. I was lucky in that situation.
Phishphreek80