With me, it's a setting in the desktop properties. Right click on an empty part of the desktop, choose properties, find the Desktop tab, choose Edit desktop button, choose General tab and in the top block check the checkbox for "Show My Computer" .
Does it work?
I'm running XP Pro on my out dated Dell computer. I went to the Start button a day ago and noticed that My Computer was missing. I don't remember how long ago it was but I noticed it was a shortcut on my desktop and without batting an eye I deleted it. I download a program called Revo Uninstaller. I deleted Winamp and wanted to see if any folders were left in my Programs Files which Windows leaves behind and low and behold it was gone. So now My Computer is gone and I use the Search tool to go to Program Files, does anyone have any suggestions on how to fix this SNAFU? Also I have no idea how it ended up on my desktop.