Sometimes things just go wrong with your computer and you might face a lengthy or expensive wait to get a supposed 'expert' to find the source of the problem.  Fortunately there are a few sites on the web that will help you out of your problems whether it be a an annoying niggle or a complete meltdown.

Computerhope is a great starting point to actually find out what your problem is and then go most of the way to fixing it if your problem is simple.  This is a Windows on only site covering all Microsoft O/S's from Windows 95 through to Windows 7.

Yes Apple Computers do break down too believe it or not and luckily Apple have a comprehensive help site available here to find a solution to your problem.

Many problems are simply annoyances rather than major issues then you need to visit annoyances.org to get fast answers to your problems via forums.

To actually watch someone fix common PC problems then you need to visit the eHowTech channel at Youtube.  This also has a range of tweaking videos to improve performance.

Last but not least and in my opinion the best is just good old Google - just be specific about your problem when you type it in the search box and your solution is never far away.  I have never found a computer problem yet that no one else has actually suffered and written something about.

Remember also that a computer problem is not a problem until you have rebooted and it still persists.