Abnormal Program shut-down

Can you reproduce the same behavior from within Safe Mode?

Advanced startup options (including safe mode)
http://windows.microsoft.com/en-US/windows7/Advanced-startup-options-including-safe-mode

How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
http://support.microsoft.com/default.aspx/kb/929135

Can you also reproduce the problem if you test with another user, you may have to create one to test with?

Have you been experiencing this problem since day one or is it a recent happening?

Try running ChkDsk to check your drive for errors. Right-click your Drive icon/ Properties/ Tools/ Error Checking.  Try it first by not checking either box (this will run it in a Read-only mode) to see if it flags any hard drive or file problems.  If it does, restart  it by ticking both boxes, and rerun it to allow it to attempt to fix any found problems.

The hard drive manufacturer will have free diagnostic software that is bootable, or that  may even run from within Windows, that will thoroughly check the condition of your hard drive.

See if System Restore will get you back to a restore point before your problem with Explorer, OR try the System File Checker.

How to repair the operating system and how to restore the operating system configuration to an earlier point in time in Windows Vista (or 7)
http://support.microsoft.com/kb/936212/#appliesto

See how many unsigned drivers you have running on your machine.  This article will guide you on the instructions but all you have to do is type sigverif in Start Run.

How to identify unsigned drivers using sigverif utility in Windows Vista
http://www.winvistaclub.com/f34.html