It really doesn't matter what you use as nothing is full proof against malware attacks. New malware comes out on a daily basis and unless that program already has the definitions installed to protect you against, then you'll just get reinfected. Common sense is the most important to keep yourself from not getting infected. The most common infection is what I call the drive-by type. This is where you browse or search for stuff and the link you click on takes you to a malicious website. Most antivirus programs have a siterep addon that tells you in searches if that site is safe or not. I use Avast and it has it, not sure if MSE does or not.
