What is wrong with my computer?

I've been having problems with my computer...today I downloaded an anti virus program, that someone suggested, and it did a scan and said that it found 14 viruses,adware,spyware, so I deleted the infected files, and now it's running even worse! When I first log in to my computer it says error connecting, could not find windows gopu fosa...whatever that is...then it's taking a really long time to load some things...my internet homepage, my school blackboard,myspace apps,ect...I just don't know what to do, I don't know a whole lot about computers! I just wish that i could start over again...is there a way to do that or does anyone else have any other suggestions? Also, I still keep getting popups!!