First of all, I must say I am not responsible for any damage done to your system as a result of this proposed solution I discovered when solving this problem I encountered as IT Support Engineer. You must do your own back up in any case!
I had tried many solutions I can Google and only this one works for me, so here it is:
1. Assuming you are using Windows 7 or if you are using Windows 8, please make sure you select the correct operating system on the top right hand corner.
2. If above doesn't work, try deleting or rename "SoftwareDistribution" folder found in your Windows Directory. For eg. "C:\Windows" (You may need do that in the Safe Mode)
3. Final step if still doesn't work, follow below steps:
1. Open Regedit
2. Go to HKEY_LOCAL_MACHINE\Components
3. Delete or rename REG_DWORD "pendingrequired=1"
4. Done! Try doing Microsoft Updates again...
Let me know if it works or encounter issues...