Computer doesn't switch off automatically.

[DB.]

I have a computer running Windows XP Home.
Until recently to switch this off I'd START > Turn Off Computer >
Turn Off. This would then tell me "Saving your settings" followed by
"Windows is shutting down". The computer would then switch off
automatically.
Then, inexplicably, it stopped switching off automatically but just
hung at "Windows is shutting down" - leaving me to hold down the POWER
button to switch off the computer.
Thinking this was a problem within my Windows I re-installed it
expecting that to resolve the matter - but again it hangs at "Windows is
shutting down".
What must I do to get it to shut down automatically again? My other
computer, also running XP Home, shuts down automatically as I wish this
one to do.

TIA of any replies.

 

[Unknown]

Check to see all programs have shut down. If something is running Windows
won't shut down.
Viruses? Malware?

 

[Jose]

    I have a computer running Windows XP Home.
    Until recently to switch this off I'd START > Turn Off Computer >
Turn Off.  This would then tell me "Saving your settings" followed by
"Windows is shutting down". The computer would then switch off
automatically.
    Then, inexplicably, it stopped switching off automatically but just
hung at "Windows is shutting down" - leaving me to hold down the POWER
button to switch off the computer.
    Thinking this was a problem within my Windows I re-installed it
expecting that to resolve the matter - but again it hangs at "Windows is
shutting down".
    What must I do to get it to shut down automatically again?  My other
computer, also running XP Home, shuts down automatically as I wish this
one to do.

TIA of any replies.

Unless you want guesses and things to try, please supply more
information and reduce the chances of malicious software:

To eliminate questions and guessing, please provide additional
information about your system.

Click Start, Run and in the box enter:

msinfo32

Click OK, and when the System Summary info appears, click Edit, Select
All, Copy and then paste the information back here.

There will be some personal information (like System Name and User
Name), and whatever appears to be private information to you, just
delete it from the pasted information.

Perform some scans for malicious software, then fix any remaining
issues:

Download, install, update and do a full scan with these free malware
detection programs:

Malwarebytes (MBAM): http://malwarebytes.org/
SUPERAntiSpyware: (SAS): http://www.superantispyware.com/

They can be uninstalled later if desired.