Though our focus is on game development and things like this, I occasionally take on the role of IT support for friends and family. After battling with a nasty collection of virii on a family members computer, I realized that Windows Update on their win7 system was gone from control panel!
Long story short, it, as well as the Background Intelligent Transfer Service (BITS) was just gone.
Naturally, I send systems home after a windows update to get the latest and greatest updates installed, so this had to be solved.
Googling around showed me a couple suggestions, some showing I needed to reinstall the operating system (or at least do a repair). SFC /scannow didn't fix anything either. I thought, that's dumb, why can't I manually add this stuff back in.
Well, we can!
Our happy command to do such is called "sc".
Before I get too far in to this, windows update DEPENDS on BITS to be running, and started to operate correctly (forcing an update while BITS is unavailable or not started will freeze your system pretty hard indefinitely).
For me, both "Windows Update" and "Background Intelligent Transfer Service" was missing from services.msc! So, first order is to get BITS back and working.
The command on an admin command prompt (yes, those are SPACES AFTER THE EQUAL SIGNS):
sc create BITS type= share start= delayed-auto binPath= "C:\Windows\System32\svchost.exe -k netsvcs" tag= no DisplayName= "Background Intelligent Transfer Service"
Should create BITS in the services registry, but wait, we're not done yet. BITS has some dependencies that should be added!
sc config BITS depend= RpcSs/EventSystem
This will add the dependencies for BITS.
Unfortunately for me, one of the viruses really messed up the registry settings for this service as well, so here is a "good" version of the part of the registry I had to import from a functioning WINDOWS 7 system as well.
Ok, with that done, I could get back to adding Windows Update again!
The same idea applied to this:
sc create wuauserv type= share start= delayed-auto binPath= "C:\Windows\System32\svchost.exe -k netsvcs" tag= no DisplayName= "Windows Update"
and again, to add the dependency...
sc config wuauserv depend= RpcSs
Both BITS and Windows Update should now be in the services window now and you SHOULD be able further configure them.
If you get access denied errors make sure you ran the command prompt as an administrator.
If you still get access denied, then you probably have malware and/or a bad virus problem. You may have to resort to safe mode, run virus scans, possibly do recovery console stuff, etc.
Personally, I ran CCleaner, AVG anti-virus, then Malware Bytes Antimalware, mostly in safe mode, and that cleaned up the problems on this system.