A week ago I kept getting messages saying oexrftno.dll has a virus and it needed to be deleted. So I searched up that file and couldn't find anything over the internet. I figured that it didn't need to be used. I found it here C:\WINDOWS\system32\oexrftno.dll. I deleted it and now everytime I start up it says error running oexrftno.dll. How do i get this to stop happening?

That is not a Windows file. I would suggest the following:

Please read THIS and after completing the steps outlined post a HijackThis log over in that section along with a brief description of your problem.

Do not post HijackThis logs in this section please.