If you can provide a little more information as to what anti-virus it is that you have or what it does, would be really helpful. If deleting an Anti- Virus is what you want then do the following:
If you have windows Vista:
Click Windows and then go to Control Panel
Go down to Programs and click on Un-Install a Program
a list should drop, find the anti-virus you want to delete and double click it.
If you have Windows Xp
Click on the Windows tab and find the Control Panel
A list of folders should come up, find the one that says Programs and Features
Double click it and another list should come up. Find the program you want to delete and double click it.
WARNING!!!!
I do not recommend that you go browsing the internet without a good anti-virus, according to experts doing so will have your computer infected with a Virus or Trojan Horse or other malware within six minutes. I recommend you use Norton Internet Security 2009 or Norton 360, both have worked great for me but in my opinion you don't need all the extra stuff on Norton 360. Internet Security works much faster and uses much less memory. Used either one if you are willing and able to shell out about $70 bucks. They are both the best in my experience, they both include a much better pop-up blocker and spam blocker. I could not trust McAfee, it uses lots of memory. Do not go to Defender-Pro, it crashed my laptop!!!!
If money is an issue you can go to Cnet.com and go to the download section, find AVG Anti-Virus Free Edition. It works good and does not hog all your memory, but you will need to find a better pop-up blocker than your Internet Provider gives you or the one that your browser provides. You will also need a spyware blocker and remover. AVG is free and so is the download from Cnet.com but I do recommend Norton. Good luck and have a happy new year!