Disk write error

It sounds like your drive becomes unavailable somwe of the time, have you ran antivirus checks?
How long are you using it when it hangs? It wouldn't hurt to reseat the ribbon cables for the hard drive. What programs are you running that can't write when closing or is it just the shutdown procedure, or does it happen at all different times?

Drive cable seating not the problem (Notebook Inspiron 8000), seated well. Length of runtime previous to problem: mostly overnight. I have turned off automatic scheduling of Scandisk and derfrag. sometimes Outlook has been running (corrupted .pst file during one failure). "SHUTDOWN" is ctr-alt-del ("task mgr" )to elicit computer response, with no response coming from the computer.

i have had this problem before usualy after i defrag the disk drive. check microsofts website they had information on this a while back also the problem may have something to do with programs that are open when your computer goes to sleep mode

Another clue: This was happening on this machine just before my previous HDD "went completely south." Eventually that drive had thousands of bad sectors, but this drive has no bad sectors (IBM 30GB 2? form). Return on a search at Microsoft's knowledge base yields this comment "Content that matches your query is not available at this time."

This will sound off the wall, but try reducing the amount of RAM on the system.

There is a bug with Windows 9X/Me where strange things can happen with over 511MB of RAM.
The bug is VERY configuration dependant.

Basically, Windows will expand vcache to the full amount of RAM, and cause a significant reduction in available resources.

I purposely limit all my 9X boxes to 384MB of RAM.

Chas