I've come across this any number of times.
Unless you feel comfortable doing the following, I'd suggest you take it to your trusted technician.
Otherwise, follow the instructions below.
Go to wsusoffline.net and download the package. (currently version 10.8)
Unzip the package
Run wsusoffline\UpdateGenerator.exe (This will have to be a short path. It will work in your users download folder or the desktop folder, however if you archive downloads elsewhere like me, it might be troublesome. No fancy characters like !@#$% etc can be in the path)
If Security warning comes up advising it will make changes, accept it if your comfortable.
With the next dialog that comes up, It'll give you some choices. x86 or x64, do you know which you're running? You can find it in System Properties.
From here, its rather simple really.
Verify downloaded updates
Include C++ runtime libraries and .NET frameworks
Include Service Packs.
The following are optional, but are advised unless you have a really good malware/antivirus outside of what Microsoft offers.
Include Microsoft Security Essentials
Include Windows Defender definitions.
Thats it, hit 'start' and let it run til it tells you its done.
Once this is done, you'll need to MANUALLY run the next program.
wsusoffline\UpdateGenerator\client\UpdateInstaller.exe
You may need to login as 'admin' or or again approve changes made.
The next dialog box, 'WSUS Offline Update v# - Installer' gives you more choices. Mostly due to the previous step. Select the same choices as you did above (Don't worry, if you forget one you can just run it again and include it again later).
This will FORCEFULLY begin the script to install the packages you downloaded in the previous step with the updateGenerator.
This will LIKELY require several reboots and WONT likely reboot on its own. The DOS box (cmd.com or command.com) will tell you to reboot your computer.
Occasionally I get a customer whose needed or had a reinstall done and Windows refuses to update. Errors or just hangs forever looking. Its likely due to the update program simply not finding the server and needing its own update.
95% of the time, I just go with this as it updates everything along the way. Eventually, the automatic Windows Update program will figure out it will work and you can switch over to that.
Good luck!