Disk usage constantly at 100%

[Vanshtomar]

I am currently running windows 10 version 2004 on my laptop 

I've made no recent changes 

My disk usage is constantly at 100% and I'm unable to open any app 

Please help

[WAWood]

@Vanshtomar 

Most likely Windows Update (WU) is hogging your PC trying to update it.

To disable WU temporarily, do the following:
1) Enter "services" in the search area (again, without the quotes)
2) When the window opens, scroll down until you see Windows Update
3) If it say Running under status, that indicates that WU is running
4) To change that, double-click on that task, select Stop under the Service status, and then Apply
5) That should stop WU -- and you should see an immediate improvement in performance

If not, then WU is not the problem.