You shouldn't try to fix this manually. There are many programs out there to do the job for you...much better at that....
Here are 2 FREE programs you can run to check for this sort of thing, which looks to me like some kind of spyware.
Spybot Search and Destroy
Also make sure to have some kind of Anti Virus program installed to scan incase it is a virus or trojan.
Here is an excellent and also FREE virus program...