Windows updates were failing to install on a computer. Here’s the steps I did to correct the issue:

1.) Reboot. This didn’t do anything but waste 4 minutes of time.
2.) Erase C:\WINDOWS\system32\SoftwareDistribution folder. Redownloaded Update Files but didn’t help.
3.) Download the Windows WGA and try to install. Failed on installation.
4.) Start off the Windows Disk and do a repair. Ended up in the same boat as before, but the computer starts up quicker now.
5.) Re-Register DLL files for windows update. This ended up working.

How to register DLL files:
1.) Open the command line (Start >> Run >> CMD)
2.) regsvr32 wuapi.dll, regsrv32 wuaueng.dll, regsrv32 wuaueng1.dll, regsrv32 wucltui.dll, regsrv32 wups.dll, regsrv32 wups2.dll, regsvr32 wuweb.dll
3.) Reopen the Windows Update window and try to update again

[edit: I had “regsrv32” instead of “regsvr32”. This has been fixed.]