Unable to connect to desktop after deleting things from driver?

I was trying to deleted a virus from my computer through "regedit" and I started to delete from thing from the driver that I was not trying to, including the problem that was messing up my system. Now when I restart my computer, I have no desktop icons to log into my internet!!! And when I try to reboot and do a "F8", I don't have reset default as an option. What can I do to fix the problem. Please help me!!! Thanks...