It seems that I have a virus, I bought the Norton antivirus, I had it before, but I never updated it. I just bought a new Norton and unistalled the old one; while installing the new norton it was taking too long, after about 15 minutes I cancelled it and tryed to install it again but it says: "another installer is currently running. Please wait for it to complete and try again". I have rebooted about three times and about 4 hours have passed but it still won't let me install it. Please help me!

First its not a good idea to piggyback your question on someone elses. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

I don't recommend Norton, this is actually one of the reasons, if you abort an install it can cause havoc. I suggest you go to Symantec's site and get their removal tool to try and clean out the partial install.