This problem is a beefy one.
To open regedit, go to computer/your OS (should be x64 or C:/)/windows
Then hit the letter 'R' until you see the icon for REGEDIT... Right click this, and choose run as: Then choose your local admin, on the user that you are currently logged into. Don't worry about a password unless your account requires one... Simply provide that if needed.
Then, from there.... This is where it gets a little tricky.
Then navigate yourself to the right pane....
There should be two things we are looking for here... The first is our SHELL... find that and double-click (or right click then choose 'modify') the value data should read EXACTLY THIS: explorer.exe If it does NOT say this, or says ANYTHING else, change it so that is says simply: explorer.exe
Scroll down in the same pane, and find Userinit... Modify this as well... The value data should read exactly this: C:\Windows\system32\userinit.exe,
Yes... There should be a comma. If this value is NOT set exactly as I mentioned... Modify it to that.
Then, close the registry editor, and do a power cycle (restart your PC, shutting it down completely, turn it off, then turn it back on using the button... Do not simply click restart)
This should give you explorer.exe back.
After that, you will still have issues opening programs... There is no easy fix for this, so I'll give you the short answer.
Create a new user by going to CONTROL PANEL.
Give that new user Admin. Permissions
Load er up.
Put all of your important icons on a memory stick or external HD
Make sure all of your programs work
Delete the previous user.
This should fix all of your problems.
Total estimated fix time: 20 minutes
This is a complete fix.... There should be no residual issue after completing these steps.
If you need more help, e-mail me at email@example.com