Partition magic stuck on updating system
It's a little more involved, but it's not difficult to do.
First, boot up into Safe Mode (see step 5), then access to the command prompt, the most basic of Windows interfaces: right-click on the Start menu, choose Command Prompt (Admin), and a text box should appear.
We're going to cover a lot of ground here for several versions of Windows and a variety of 'stuck' scenarios, so you may have to tweak some of these steps to suit your situation and software.
The first point to make is that interfering with updates that aren't actually stuck can cause a host of problems, so you want to make sure they really are stuck.
Back in Windows proper, navigate to the C:\ Windows\ Software Distribution folder, and delete everything you find therein.
Windows 10 has actually streamlined the update process, so you should be seeing fewer errors.
Microsoft feels your pain: it knows the update process can cause problems every now and again, which is why it's developed a troubleshooter program specifically for it – search the old Control Panel for "troubleshooting", then select 'Fix problems with Windows Update' from the list on-screen.
You're not going to break anything by doing this – these are just temporary files Windows creates so it knows where it's up to, and Windows Update will create them again from scratch.
With that done, go back to your command prompt window and type "net start wuauserv" (Enter) then "net start bits" (Enter) to get Windows Update and its related background services up and running again; hopefully this trick should be enough to kick-start the update that was previously stuck.
You can find the option via the Recovery tab on the Update & Security page in the Settings app – note that third-party apps are removed too, so these will need installing again.