Klez Virus Problem

I have had a problem with this as well. I have Mcafee and have kept up with all the new sdat upgrades, but am still having problems. Someone mentioned blocking executable files? How would I go about this? The virus scan doesn’t show any infectedfiles, yet I know there is a problem, I just can’t find it. I keep getting these stupid emails, and I don’t even view them and it pops up! It’s very frusterating, because just when I think I am close to getting it cleaned up, someone sends it to me again! I appreciate any help with this. Thanks,
Diana