If it was AT & T/McAfee then run the MCPR removal tool listed under Useful Links above and reboot then retry.
If it was some other brand of protection then you'll have to check with AT & T as to what it was.
it is the at&t/mcafee antivirus software that i am trying to reinstall. the mcpr removal tool did not work. any other ideas?
I would then contact Technical Support Chat via the "Useful Links" at the top of the page.