If it's anything like the thinkpad I have (2628) then there's a screw about 1/2" in diameter on the bottom of the case...I believe it's on the same side as the CD-ROM drive. Anyway, you unscrew the screw with a nickel (this is straight from ibm tech support

), then the hard drive tray should slide out. They made it really easy to change hard drives..no need to take apart the thinkpad. Well, at least that's how it was on mine (A20m). Hope that helps...good luck.

As for your replacement hard drive, they come in two sizes (9.5mm and 11.5mm), so make sure you know which one to get...I believe all the newer ones are 9.5mm.