Virus .udjvu

Yesterday I was using my computer normally then suddenly a popup showed telling me that there was updates installing and I knew that it's not from Microsoft  as when I opened the source from task manger I found that it's not related to Microsoft updates so I click on end task then I tried to open Windows defender but it showed this message " page not available Your IT administrator as limited access to some areas of this app, and the item you tried to access is not available. Contact IT helpdesk for more information. Then I found that a program called windows powershell is installed by itself .. Then the screen blacked out showing only this message when I tried to open Task manger " Task manger has been disabled by your administrator" 

SO I tried to restart the my computer but couldn't open start...after managing to restart by pressing the  power button for awhile to restore windows from a restore points , there was three but all failed and also repair failed so click on reset my computer but keep my files ..when it finished I found all my files "pictures , programs , pdfs, doxc, " all of it ended with this extension

.udjvu

like in the picture attached 

So How can I get my files back and open them?

"when I tried to use snap tool I didn't find it"