Fuck my life

Okay, guys, I need help. I rebooted my computer because it had been on for 3 days, and upon rebooting it, explorer.exe is now missing. Completely missing. Everything else works fine, but I have no desktop, startbar and can't open folders.

What happened and how to do I fix this?!

Try running explorer.exe manually via task manager (ctrl alt del), if this fails , try booting into safe mode.