HP Compaq nx9040 release with windows XP, For model like this to work with windows 7, the problems would be the graphic and audio because it uses Intel 82852/82855 GM/GME Graphics Controller Driver and Conexant CX20468-31 AC97 Audio Driver. So here is my initial suggestion for the Drivers:
Intel 82852/82855 GM/GME Graphics Controller Driver
To install this Driver follow this guide here:
Conexant CX20468-31 AC97 Audio Driver
To install the Audio foolow this Guide here:
If you still have problem swith audio leave you comments i will guide you through the installation.
The other driver such as wireless will automatically installed, if not try these drivers:
If you have Intel Wireless:
Intel Wireless LAN Driver for Microsoft Windows 7
If you have Broadcom Wireless:
Broadcom Wireless LAN Driver for Microsoft Windows 7
If you have any problems leave your comments.