Windows Wont Shut Down

Friend has Windows XP Home.
She uses Outlook Express, IE & Quicken
Nothing more.
It has begun hanging during shut down process
she's been just "turning it off" which she knows is not good to do.
I'm going to attemp a REMOTE ASSISTANCE tonight as she's in another state.
Before I do, does anyone have any suggestions of what to look for.
I was first going to go into MSCONFIG and shut down unnecessary start up items, but this must be come driver that's hanging.
Do I need to shut down everything one at a time and shut down until I discover what's hanging? This would be difficult to do remotely.
Any ideas?
Linda