Signed up for McAfee thru TWC cable, now get all kinds of pop-ups, some telling me that my computer has been hacked.

I signed up for McAfee thru TWC cable, and now I get all kinds of malicious pop-ups telling me that my accounts have been hacked, and if I shut down my computer all of my personal, along with all my credit card info will be distributed all over the web, and to other hackers! I get little ads popping up in the middle of pages that I am trying to read, and now my Yahoo mail is sending all of my inbox e-mails straight to my trash bin, before I even look at them,in which I have my outlook mail forwarded to. Coputer runs slower, and always get driver update ads popping up, and wanting to sell me these appps. to speed up my computer, and take out all registery errors,amongst other things, saying that there is 2,000 some odd things run with my computer, and says it does a scan, and it will take care of them if I buy this program