Windows Desk top Remote Program.

VNC rocks my socks.....if it's set up at the other end or you have a semi tech savvy person on the other end of the phone.  If you can swing it, I use LogMeIn.com's ITRescue product.  I send an email to the user with a link and we hook up through teh interweb.  Good stuff.....but it costs....I like like 1K per seat.....but it's priceless when I have someone in Minnesota call me for support.....damn national sales force......