Can you open the Action Center on the taskbar > Maintenance > View reliability history > View all problem reports
Can you right-click on a few of the "Windows Explorer" "Stopped working" errors > View technical details
What are the details of the errors?
There is a "Copy to Clipboard" link at the bottom.
Also, the problem could be a problematic third party context menu handler.
The following link has some info and a download to ShellExView which you can use to selectively disable third party context menu handlers to find out a problematic one:
»windowsxp.mvps.org/slowrightclic ··· lick.htm
You could try disabling all non-Microsoft context menu handlers and then, if the problem resolves, re-enable them one at a time to see which one was the problem.