Dell XPS 400 is a desktop PC released in 2005, and Dell officially only supports for it Windows XP (32-bit and x64), and Windows Vista 32-bit. I installed Windows 7 64-bit anyway on it, and it is able to detect and install most of the devices, including display adaptor RADEON X600, in the old PC. The only exceptions are the Ethernet LAN card and Wi-Fi card. Windows 7 x64 complains it could not find the driver for the LAN network device. It seems that it could not even see the wireless adaptor.
According to the Dell support website for XPS 400/Dimension 9150, if you expand “Network (2)”, you would see in the list
- Dell Wireless 1450 (802.11a/b/g) USB 2.0 Adaptor (only has Windows XP drivers)
- Intel PRO/1000 Network Connections (has Windows XP and Windows Vista 32-bit drivers)
Unfortunately, you cannot find Windows 7 64-bit drivers there for them. However, the exact names of the device provide important hint about finding the correct drivers.