If you are running Windows Vista and you cannot start the Background Intelligent Transfer Service, you can download the BITS Repair Tool to fix any problems corrupted BITS files.
Start, Run and type in the following command:
The Dependency Walker will pop up and you will get an error message if any of the required DLLs are missing. You also want to check the DLL dependencies for Windows Update:
If you simply get a window with a whole bunch of DLLs listed and no error messages that means all the appropriate DLL files for BITS and Windows Update are correctly installed on your .depends.exe %windir%\system32\wuauserv.dll
If you get an error about a DLL not being found or that is missing, then it is best to run System File Checker, which will copy back all of the original Windows DLL files. Go to Start, Run, and type in CMD. At the prompt, type in
Afterwards, reboot your machine and hopefully your problem will now be fixed!sfc /scannow