For months my Windows Firewall would not function.  I tried Microsoft and a dozen other repair methodologies, but nothing worked.  I resorted to finding an online Firewall [freebie!], but they were not satisfactory for one reason or another.  I decided to try a repair once again and came across Tweaking.com.  There was a simple little "download" to repaid windows firewall, and I tried it.  It took 86sec to repair, and now functions as it did when I first got this computer.  Bravo!
Now, if there was just another such program to allow updates rather than the odious "8024200d error", I would be ecstatic.  Updates are never completely successful, though I do utilize their Troubleshooter and it works to a limited degree.  I feel certain that anyone that can write a program to correct a broken firewall, will find this one also fairly simple.  Bon Chance!!