None of .exe files will open (windows 7) and I don't know what to do!! HELP!!!!?

Well yesterday when i had tried to turn on my computer and open my browser it told me to select a program that i want to use to open it with and i was lik wtf?!? so then i tried to open another browser (cause i downloaded 4 different browsers) and the same message popped up. but i noticed that its not all my programs that won't open, just my .exe file cause like my control panel opens and stuff. after all this i had tried to call the laptop company, HP, and they said its probally because of a trojan, spyware, or malware because i hav an anti-virus sofware installed. they said they could help but it costed money so i could accept becuase im on a tight budget. and the other day a program(win 7 home security) popped up that said i had 20 somin infections! so i removed them but now my .exe files still won't open. i can't access the internet(except once when i tried to uninstall google chrome and IE popped and stayed up but i exited out see if it would work now[dumb idea]) but i can access task manager and CMD if that help so please HELP!!! its like hell cause i have been having alot of computer and printer problems along with testing so im really fustrated right now. oh and if your wondering im using my ipod touch to access this and the internet for solutions.