I have been fighting this problem since December 31 2010 when it occurred. My system no longer listed the BITS service at all. I had a bit locker but the service was not in the system.
Some of the updates you could download in a service pack a while back so I had a partial update.
We had a power failure here and that is what cause my error. Being the stubborn sort I was not willing to do the wipe it clean option unless I could no longer secure the system.
I installed both the registry keys and for the first time this year the win-update actually worked. THANK YOU!
BTW this was the first issue I have had with Windows 7. Thankfully we finally have an os that is more stable then win95 was. Can't say that about all the one's in-between them. LOL