HP Pavilion dv9000
The HP Pavilion dv9xxx is not officially supported by HP for Windows 7 upgrades.
Here is the HP document showing the supported models. HP notebook series supported with Windows 7
-> For more specific information on how to upgrade you'll want to read the Win7/Pavilion DV9xxx topics in the HP support forums.* Windows 7 Upgrade Guide for dv6000/dv9000 models