Your DV9000 series notebook computer comes with a second hard drive bay. Unless you custom configured your machine at HP, it’s probably sitting empty. Most pre-configured systems at stores don’t have this second bay full. The new Santa Rosa intel computers is one example. I wanted to add another 160 gigs of storage for 320 gigs on the road. The only problem is you can’t just install a drive, you need to special order a “caddy” direct from HP. This part will allow you to install your 2.5″ SATA notebook drive in the second drive bay on your HPDV9000 series notebook computer. HP Part Number: 434106-001 You go here to order it: http://h20141.www2.hp.com/hpparts/default.asp?cc=US〈=EN If you have a DV9535 (new santa rosa) it may not say that this the correct part, but ALL the DV9000 series notebooks (so far) use this hard drive mounting kit. The only thing is it costs $39… a rip off but what are you going to do.. haha Above is the kit it comes with a tray and a special pin adapter and 4 screws to install the drive. Installation is easy, just attach the pin adapter to the SATA on the end of the drive, then mount the drive to the tray… and just drop it in the second bay on the underside of your DV9000 / DV9535 laptop. Then go to the disk manager in windows and partition the drive as you like. Works great !