Dell Precision 690 won't shut down

Do you have message "It is now safe to turn off computer" when you shutdown?

No. The procedure I use is "START", "TURN OFF COMPUTER" , select TURN OFF and it proceeds to "shut down". There is no message in this sequence.

Try clearing out msconfig, like go to start up items and disable everything and click ok and then restart the system. Check if ever that can help.

I've been through that with Dell Tech Support and it did not help. I only retain the Start-Up items I need. The rest are not selected, and I am in Custom Start-Up.

This will be related to an application that is running in the background that Windows cannot kill.
You could try to force a shutdown by going Start->Run Enter shutdown -t 0 -f -s
Once the PC has done a clean shutdown, try rebooting again and see if the problem is resolved.
(Some PCs will not access the - in the commands above. If so replace them with / )

Otherwise you will need to have a look at what processes are running and experiment killing some and then shutting down. Once you have identified the application you should remove it from startup as ScanR suggested.

This app is much better for identifying applications than Windows Task Manager.
http://www.microsoft.com/technet/sysinternals/utilities/processexplorer.mspx 
It may help you look at these programs running.

http://aumha.org/win5/a/shtdwnxp.htm

When does the problem starts happening? You might want to perform system restore if ever that can help.

Also, try the User Profile Hive Cleanup Service (https://www.microsoft.com/downloads/details.aspx?familyid=1B286E6D-8912-4E18-B570-42470E2F3582&displaylang=en)

Does it shut down properly in safe mode under the admin account?

Thanks Guys for all those comments. I need to spend a bit of time working on them and I shall let you know the results.

One other factor I mentioned is that some time back I installed and ran Iolo System Mechanic to see whether it would identify and clean-up issues. Is it possible that System Mechanic could have wiped out a link or process that enabled or affects shutting down the computer?

It is possible, which is why I suggested a second clean install to isolate whether it is software or hardware.  That product had some bad releases in the past: http://www.forbes.com/technology/2007/04/25/iolo-system-mechanic-tech-personal-cx_de_0425iolo.html

Callendor, as far as I know this can only be done on the C:/ drive which already has the present system. To wipe this, a second clean install means rebuilding the system from scratch. Three days of work. There must be an easier way.

I believe basing on all the sugestions here, the best solution that we can have is just to  clean up everything. It's hard to deal with but I believe that will be our best solution.

Create a second small partition of about 10GB and you should be able to install a basic OS.  This assumes you have all the drivers for the Dell.  A product like Boot-It NG http://terabyte.vshost.com/bootitng.html will let you create another partition, and I think it has a free trial download.

Is it not the case that when one creates a partition on an existing drive it wipes the drive clean, or runs the risk of doing so? And what is a "basic OS" The only one I have is the Dell OEM WINXPSP2. I'm not sure how well a re-install of that in a partition of the C Drive would work.

OK, I see - that application is supposed to do it safely. How trustworthy? What is the track record of people using this software followed by reinstall using the Dell-supplied OS and drivers?

What you want to do is resize the existing partition to a slightly smaller one so that you have room to create a second partition.  The safe thing to do whenever working with partitions is to backup all important data, just in case something goes wrong - you never know when the power may have a glitch, someone trips over the plug, a card comes loose, etc.  Boot-It NG will also make a backup image of the drive to a second hard drive or external drive.

Boot-It NG is recommended by several top experts on this site, and I have not seen anything bad about it.  Installing the Dell OEM disc should be a simple matter, as long as you specify the right partition when it prompts you.

Thanks Callandor. I shall consider it.

I'm still working on this problem, but in a different way. I'm trying to diagnose the conditions in which the problem occurs. This is less interventionist than approaches recommended here and by Dell. It will take more time but it is less risky. I think it could be useful to anyone else experiencing this problem if the thred were kept alive until I have an opportunity to report back any results from this approach.

Forced accept.

Computer101
EE Admin