chrysalis said:
I too have this issue, it seems to be recent during past month or so.

Its not very frequent, I had a explorer crash 2 mins ago and one before that about 3-4 weeks back, also one or 2 on spare machine.

Whats annoying about it is all explorer windows close when it crashes, even tho I have the use seperate process option enabled.
chrysalis,

*Type event viewer, in search (by start button) and look for errors that may show the cause of the problem.
Look for critical errors (they have red in the left column ).
Note critical errors that say app hang, app crash, or anything that relates to the problem.
Google for more information.

* Try a clean boot, or boot into safe mode.
Does the behavior persist?
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
Safe Mode

* Run DiskCleanup
Disk Cleanup - Open and Use

* How to Repair Windows 7 System Files with System File Checker
SFC /SCANNOW Command - System File Checker

* Then run checkdisk (chkdsk).
Disk Check