So you want to sell your old laptop? Desktop? Maybe even a server or two? Good for you! Money in the pocket is much better than filling up landfills with monitors, cpus and the like.  I have just two key points to remind you of, and these are in order (so if you have a short attention span, just read the first one then move on...)

First, if you are going to sell anything that has a hard-drive or some other semi-permanent storage device attached to it (this includes network-attached storage or NAS, too), then be sure that you have completely wiped the hard drive of any personal information.  The last thing you want to do is have your new $100 bill from the sale go toward the $1,000 (or more) you've spent trying to clean up your credit history.  In today's day and age, you really can't trust that the anonymous person on the other end of the transaction isn't going to try to pick up a couple of stray credit card numbers that you thought you'd deleted.

If you think this doesn't happen, think again.  I purchased a Snap Server which is a network-attached storage device (only 20GB, just enough for me to tinker with) that was offered up on Ebay a few months back.  I had no ulterior motive, I just wanted someplace to archive some email and files that I didn't want to lose should the hard drive in my PC fail.  When I got it, I was surprised to find that it had been used as network shared drive for a small business.  I have no idea of the actual events that led to the device being put up for auction, but I do know that they didn't do their employees justice by leaving all of their human resource records on the drive.  They hadn't even tried to delete them!  That's just pathetic.  Of course, I wiped the drive for them before I started using it, but maybe somebody else wouldn't be that nice.

Want an easy solution?  I highly recommend using a software program to effectively delete sensitive information from your PC.  Personally, I use a program called Eraser (availabe at heidi.ie) I've been using it for a few years.  It adds an option to the typical Windows Recycle Bin that allows you to not only delete files, but completely wipe them out.  Without going into significant tech detail, it works by overwriting the deleted files several times - ensuring that even if someone wanted to recover them, they wouldn't be able to.  Remember, better to be safe than sorry!

My final tip for anyone selling their computer on Ebay is to be realistic about the price of your prized possession.  There isn't much demand for 10 year old PC, unless you happen to find a fanatic dying to add that particular model to their collection.  If you've invested in upgrades like video cards or other fancy doo-dahs, think about selling them separately from your system - you'll probably make more than trying sell everything in one package.  Also, remember if you're selling any monitor other than a new-fangled LCD, you're probably going to have to charge more for shipping than anyone wants to pay.  Leave the old cathode ray tube (CRT) monitor out of the sale and you'll probably wind up with more money in your pocket!