Few suggestions.
>> Did you make any changes to your system prior to this happening ... install new programs, new hardware etc?
This "explorer.exe constant crashing" can happen if newly installed programs/hardware added a "right click" option somewhere.
Uninstalling/reversing recent changes may help.
>>Have you tried invoking System Restore back to a date prior to when the trouble started? (don't worry about data; only the system settings/programs etc. will be taken back in time).
>>Try reinstalling the Internet Explorer browser. (Before anyone says anything, yes, I know we're talking about explorer.exe here but the two are linked. If you get a glitch in IE it could affect the running of the explorer.exe shell).
>>Your computer could have developed a problem with memory. You could check the performance of memory here ...
www.memtest86.com
Good luck.
Let us know how you get on.
OJ