Hi Henry,

If it is happeinnig for all your exe files, I would suggest you to not only rely upon Mcafee for your computer security.
I recommend uninstalling McAfee first by following the below steps.

1. Type Programs and Features on your Windows Start Screen and select it from the list of results.
2. Locate the McAfee program you want to uninstall in the list of programs.
3. Right click the McAfee program and choose uninstall.
4. Select the check boxes for the items you want to remove, then click Remove.

For an anti-virus program, I recommend eSet NOD32 or Kaspersky, if you
are willing to pay for it.

If you want a free anti-virus, I recommend
one (do not run more than one antivirus program) of the following
three:
Avira AntiVir
Avast
Microsoft Security Essentials

I hope this helps.

Regards,
Lokesh