Uninstall mcafee, install Microsoft Security Essentials, and try again. McAfee does not like Real Flight. Known issue. Don't forget to throw away your Junk McAfee disc.
I don't run any anti virus software at this point. I haven't experienced any problems from this practice. I simply use ccleaner regularly. I was using MSE months ago and I found that its background services, particularly the monitoring service to be a CPU cycle and memory hog. When I uninstalled it I noticed a performance boost. Anti virus software, in my opinion, is like screen savers. Unnecessary if you browse and email responsibly. Your mileage may vary.
This problem is indicative of anti virus software of all brands. Too many false positives.
I found that this is particularly true when it is first installed and if the program has not run a full scan recently.
It does tend to scan system files at startup and allocate memory while doing so, also slowing down boot times a bit, but if you let the machine sit for 1-2 minutes ( spinning disk ) before working with it, the effect is mitigated.
Running a full scan once a week seems to reduce the files it scans, as if it is keeping a log/listing of what it has looked at recently.
Still it is not quite as bad as other offerings that do the same.