Windows 10 'app didn't start' error for all default apps!

Hi!
I have been using Win 10 for about 1year now; had some glitches,this one is really troubling,hence the post.
My system unfortunately contracted some malware while browsing,including Trotux
Not being much of a Tech expert,I rambled through what all I could lay handson,used AdwCleaner & MalwareBytes and was happy. But to my utter despair I could no longer use many Win 10 functionalities; cant acces the taskbar/start button,cant open pdf's with microsoft reader,windows photo viewer crashes,groove music crashes and the Store is nowhere tobe seen!
Tried Safe booting,uninstalled the apps with cmd,tried powershell tweeks..none with results..
I will be immensely grateful for any help
Thankyou.

This has been a recurring problem for a few users since these Modern Windows Apps were first introduced in Windows 8. It's a permissions problem, probably in your case changed by the malware you had.

Cause


Registry and or file system permissions may have been changed from their defaults.

The "All Application Packages" group (a well known group with a predefined SID) must have specific access to certain locations of the registry and file system for Modern Apps to function properly.

https://support.microsoft.com/en-gb/kb/2798317

sfc /scannow may help restore the defaults, or a 'Refresh this PC' or even an in-place repair install may be necessary to repair the damage done by the malware.
Repair Install Windows 10 with an In-place Upgrade