Three of the many reasons why Explorer crashes;
1] Viruses or other malware
Update your anti-virus and run a full scan, preferably in Safe Mode.
Also, download, install and update the free versions of Malwarebytes Anti-malware and SUPERAntiSpyware.
Then run those, preferably in Safe Mode too.
2] Corrupt files.
Explorer means many things. It is Windows Explorer, Internet Explorer, your Desktop, your My Computer, My Documents, etc. So what affects one may affect all because they are closely integrated together into the OS.
If Explorer crashes on bootup, then this might point to a corrupt file on your Desktop Generally corrupt files mean corrupt image or video files, where Explorer attempts to 'render' them whilst displaying the files, but I imagine some other corrupt files may also cause Explorer to crash.
Certainly, when attempting to open any folder which has images or videos in it, and where the View option is Thumbnails, Tiles, or Icons, Explorer will crash when it comes across a corrupt file.
The workaround there is to identify any corrupt files and remove them.
3] Internet Explorer.
As I said above, Explorer and Internet Explorer are closely related and integrated. If IE has any bad, corrupt, or infected Add-ons, then this may also cause Explorer to fail. Remove all Add-ons to see if that helps.