From looking at Wikipedia
and the CAC
home page, I don't think the Department of Defense is going to let you use your smart card to log into your personal computer. You could obtain a USB- or ExpressCard-based smart card adapter and use another smart card to login, or if you don't want to carry another card, perhaps add a fingerprint reader. AuthenTec
(formerly UPEK) makes a number of USB-based readers. I've been using the original Eikon model with Microsoft Windows 7
x64 SP1 and it works quite well.