Make a JING or SCREENR recording
In order to get help with a problem, you need to be able to describe it accurately and completely.
That can be tricky. You may not know the correct terms to describe what you're seeing. It might be difficult to remember the exact sequence of steps it takes to replicate a problem. Or the problem may only arise when you do things a certain way that's a little different from the way someone else assumes you're doing it.
JING's the thing
JING is free screen recording software from TechSmith, the makers of the world-class Camtasia screen recording/editing program.
JING can record a movie of anything you do on the computer (including voice narration if you like). It can then upload the recording to TechSmith's Screencast.com web site, which offers free hosting for your movies. Once you've uploaded the recording, it gives you a URL that you can paste into an email or a support forum message. The tech support people who're helping you solve your computer problem can then view the movie just by clicking the link.
Or SCREENR it
SCREENR from Articulate is another easy-to-use solution. It's web-based, doesn't require any downloads (though it does need Java enabled on your PC), and offers a few more upload options when you're done recording; easy upload to Facebook for example.