It takes something like 10 min. to shutdown.
125125
You probably have lot of back ground softwares running... Like Anti virus, Google Desktop Search, Konfabulator, etc which takes time to shut down... Check how many processes are running by doing Ctrl-Alt-Del and checking the processes list.
663571
Your computer could have been heated too much.Try working on it after shutting down your pc for an hour or two.
368813
press and hold the power button on the tower it will shut off
51558
I think your monitor is about ready to die.
592314
It is shutting down. Your computer just takes a long time to shut down. Maybe it has many processes active or you need to cleanup your files.
318265
try clicking altogether ctrl+alt+delete and click shut down. if it's still not working, you have to contact your pc manufacturer
323243
Press power button and hold for MORE THAN 4 seconds.
156437
could be a hardware or heat related condition. if the fan for the cpu stops working, the cpu will get too hot and the computer will shut it's self down.
141920
Start -> Run: shut down -s -t followed by the period (in seconds)\n;)
603326
Maybe the times it disconnects are peak usage times and so many people being on-line at once it causing service interruptions.  Call your provider and ask them and tell them you want the problem fixed.
130904
Well It Could Be Solved By All Those Things, But You Haven't Specified Exactly What Happens After 10 Mins. Coz If The Comp Restarts After 10 Mins It's Probably A Trojan. And Most AVs Can't Detect Trojans That Easily. For That You Should Use AVG, It's Kinda Good. If It Is A Virus Or A Trojan That Still Can't be Deleted It's Probably A Sasser Worm, That Can Only Be Gotten Rid Off By A Low Frequency Format. Trust Me This Works Coz I Had The Same Problem!
456643
not for another 8 mins
232632
Just plug the meter and shut up......
518441
Sounds like your processor is over heating...that will definitely shut down your computer.
356662
Maybe the computer went into power conservation mode. Try pressing the power button.
451087
It's currently down for maintenance.
504369
Then unplug it.  Sheesh.