This is a common problem.. I went to download a program I have used in the past and it installed some adware on my machine.. Took quite a bit to slap it down (Finally succeeded).
If all else fails google: How do I get rid of __________ (fill in the blank with the program that is bothering you) some solutions are harder than others, but usually they are the ones that work best.
I really think when jerks do that (I kind of wish I'd have done a bit more research on the one that bit me) Folks would send them a thank you note.
SUBPOENA
You are to appear in the ## circuit court
State of ____ located at ___address___
to show cause why you should not pay
__your name__ 1 million dollars as penality
for installing your mal-ware on his computer.
That kind of a "Thank you" note.