Need help with McAfee

I posted this in the "software" forum...but think It may have been the wrong place...cause it gets read several times...but no answers. And since yall are the virus pros...you might be the virus "software" pros too....so here it is

My husband just bought McAfee virus software to put on his computer. But it slows it down SOOOOOOOO much I was wondering if there is a way yall know of to configure it so it only runs when he logs on to his user acct. When his son or I use that computer it is only to play games so there is no threat of us getting viruses (they are offline games) But still we have to deal with the slow laggy effect of the McAfee.

Since my husband is the only one who could possibly get a virus on that computer it would be much better if there is a way to fix it so only he has the virus stuff running.

Any Ideas??? If not...does anyone know of ANY virus software that CAN be configured to only run on specified user accounts??