Immediate Response for recent problem

I have received a pop-up supposedly from McAfee for the past two days. I have three computers, two using XP SP3 and one using VISTA, and all have had same pop-up.

It says "Immediate response required to check a recent prolem which may have affected your computer". It then goes on to say click on the McAfee product in my task bar, click on Updates and the solution will be downloaded automatically.

Is this a legitimate fix for a McAfee problem? Does it really come from them? What problem does it fix? Will it leave a virus?

I haven't received any answer from McAfee and I don't know what to do.