Help- McAfee Registration pop-up at start of computer

Hello,

I'm running a WinXP O/S on a Dell. I've only had to do a system restore once in the last 2 years I've had my laptop- last summer. Since then, whenever I turn it on, McAfee's original virus program (they've upgraded- I get a "red/ white box") asks me to register, inputting user name and password. I do so, nothing really happens, then I have to close the pop-up to go further. HELP- how do I erase this action and just fire up my laptop w/out the McAfee box?