Well, from the look of it, it looks pretty good, but I don't have Windows so I can't really test it ^^
Doing small anti virus scripts like this is good practice, but it's not really a good way to really solve malware issues on the computer. It is, however, good when you need to shutdown a process quickly and have it remove the infected file quickly before the computer turns off (with winlogon.exe for example it does that, although shutdown -a will counter it).
Good job!
