More info may be helpful, i.e. exact Operating System, computer make/model, age of computer.
Try using System Restore to go back to a date/time prior to when then the problem began.
Run anti-virus, anti-spyware scans and remove any malware found.
If any viruses or spyware are found, remove them. Then right click on My Computer > leftclick on Properties > System Restore. Place a checkmark in the box beside "Turn off system restore on all drives." Click Apply. Remove the checkmark and click Apply > OK.
If the above doesn't fix the problem, do the following.
Immediately after the problem occurs, do you get an error message? If so, please post the exact error message.
Also, immediately after the problem occurs, go to Start > Control Panel > Administrative Tools > Event Viewer. Double click on "Application." Double click on any Error or Warning that may be listed at the top, or that coincides with the time of the occurance of the problem. Click on the Copy button which is directly below the Down arrow button. Paste the error report to a new post in this Forum thread.
Charlie
While operating Windows Explorer, if I expand any particular file, and click on the folder within, Explorer just shuts down. Can anyone please assist me in curing this problem?

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