If it was already slow, adding an antivirus program that is monitoring actively is always going to make it worse, the nature of the beast.
You might want to look into overall Windows well being applications that still support XP, Boostspeed by auslogics is one program I recommend, and I am still using in Windows 7 and I know it supports 8 now as well.
It's roughly $30 a year to keep up to date, but it's been my favorite over several years now, and I have tried others.
If you have no budget, I would try apps at:
Mz Ultimate Tools
Be sure to get the registry backup program first and use before any other.
Here is link to the XP tweaker by them, I checked their site and file support there might be dicey, he hasn't updated the apps since 2011, it's all freeware:
http://www.softpedia.com/get/Tweak/System-Tweak/Mz-Ultimate-Tweaker.shtml
and one for the registry backup program:
http://www.softpedia.com/get/Tweak/Registry-Tweak/Mz-Registry-Backup.shtml
Do note this is a Windows 7 forum, not XP, there should still be XP forums, somewhere, I left XP mostly in the dust for 7 myself, so I can't recommend one.
OP is a double poster, is this 2 different PCs or you trying to use this forum for your job? :devil:
[Double posting is possibly a bannable offense in some places, just friendly FYI, in case that wasn't clear.] It's like calling your IT dept. and opening two tickets for the same issue; a major waste of their time, and time=$ and I have noticed this site has moderators that do ban.
You need to run CPU-Z found on cpuid.com for all the details of your system, irregardless of where you post, if you expect to get far quickly, otherwise it starts out with folks just wanting those details before they start on step one of troubleshooting, usually, if you haven't noticed a pattern by now.
