Everything, but Security Essentials is one fits all.
Security Essentials is made just for Windows,
it free
The money that you spent is gone. I cannot change that.
The question now is which is the best.
MSE is used by most of our membership
It is really effective
It uses little resources
Now to your question
See the initials on my Avatar BSOD Squad
It means that I handle BSODs, if you dont know what that is your lucky
MSE is the only anti virus, that I know of, that has never caused a BSOD
Everyday that you add software, make changes etc, may cause the problem with your current AV.If it were my computer, I woiuld make the change
Start with a system restore, use MSE for a while, if not happy go back with the Restore
Bottom line, however, its your decision. What you have may be fine with XP
Vista and Seven are different.