How to Uninstall programs in xp

Hi to all,

i’m using windows xp. It was working fine upto last month. Now i have a problem in uninstalling programs. when ever i try to uninstall some programs in add/remove programs, i’m getting remove option on that, but for some software it’s showing and i can able to Install. I thought it would be caused by virus, So i scanned my whole harddisk with mcafee 8. No virus has been detected. Can any one help me for this.

Thanks in Advance