Bitcoin Explorer - Truth or did i just got my wallet stolen?
According to a post by grue, the program from the website adds another executable to system startup, so it certainly behaves like a virus. You should get your computer checked.

Advise for the future - don't trust any .exe file unless you know the source or the owner. If you're not sure whether to trust someone or some website, ask either here, or on the forum. The community is quite sensitive about security and you can be pretty sure to get some good feedback if you ask.