"Active Shield" for McAfee won't allow my computer to start up!

I have written a previous message stating how my computer was used at the office with no problems until I bought it home and installed McAfee, AOL and other programs. I did not have internet at the office. Now with McAfee there seems to be some conflicts...can anyone help!  I have to start up my computer at least 4 to 5 times  and then it states something about my active shield for McAfee.  Thank you so much for your help!