Had a fake virus scanner virus. Now my computer is messed up?

I had an often invaded fake anti virus program that was usually fixed easily enough, I had another attack today, And thought I had gotten rid of it..But apparently did not..I thought I found the file associated with the attack, And deleted it completely.. Something called Cob, Cab, Cobi...Or something along those lines..I could be way off...Now, Whenever I try to start any program it always asks me what file I want to start it with, The association screen pop's up asking what program I want to use to start it...And nothing will start!..I can't even go into safe mode, Or do any kind of system restore! It just wont let me..It wont allow me to open any files!? Any ideas on how to help this issue?!