its probably a windows explorer shell extension..
you can use this program to disable all non microsoft ones until you find
the one that is the culprit..
http://www.nirsoft.net/utils/shexview.html
download
http://www.nirsoft.net/utils/shexview.zip
unzip it. this does not need installation, and run it.
then right click disable all NON microsoft shell
extensions (usually colored in PINK)
do a restart and your pc will most likley stop crashing the explorer
also do a scan for viruses and spyware-malware
tell me if this helps