two versions of norton on my computer

I was recently trying to download some more anti spyware stuff on my comptuer.  I currently have Internet Security 2012 on my computer.  Well I could not download anything else because it stated that it was incompatible with my Norton 2009 antivirus.  I do not have Norton 2009 antivirus only Internet Security 2012.  Can you have two norton versions on your computer at one time?  How do you delete one without deleting both of them.  But if I need to, how do I delete them both and reinstall the most current?

 

blossomaime