You should never have more than one anti-virus and/or more than one anti-spyware/trojan and/or more than one software firewall (including the one built into XP, unless the other firewall is designed to allow that) program running at the same time - make sure you don't.
"...is this due to the security software or is it possible I have a virus?"
It could be, and it's possible.
Un-install any similar you aren't using. Some security software won't install properly unless you un-install other similar software first, even if the other software isn't actively running at the time.
You could try un-installing the security software. If that cures the problem load some other software - e.g. Grisoft has the very good AVG free anti-virus software, and an anti-spyware/trojan program that is free to download and works as a full version for 30 days, after which it reverts to the free version if you don't pay for it.
Or I've been told the 2008 versions of Symantec Norton software no longer bog down your comouter like earlier versions did.
You could try doing a Full anti-virus and anti-spyware/trojan scan.
Mrhack
