Been having issues with my laptop really since about Thursday when my windows updated, mcafee has then since been telling me that my mcafee is off along with my antivirus and spyware and even when I try to turn it on it does nothing. This has lead to my computer when on google either not working or freezing and not responding or being rather slow.
If this happened after a Windows update it would appear to be a problem caused by Microsoft rather than McAfee. Have you had a look on the McAfee and Microsoft forum to see if others have had a problem.
My advice and that of others on the forum would be to uninstall BTVirus Protect/McAfee. It can cause problems on some computers and is a resource hog. It always seems to be just one update away from another problem. Do a search of the forum to see the problems. There are far better free antivirus programs available such as Avast Free and AVG Free.
If you do want to uninstall BTVirusProtect use this guide and make sure you use the BTVirus Protect/McAfee removal tool after you have restarted your computer.