I have found that in many cases there are no Windows 7 drivers available from the manufacturer because Windows 7 is either hosting them, or has written them.
Some of these drivers may not be full featured but will function.
I think MS did that because of the fiasco with Vista and drivers caused Vista to be a bust.
At any rate, if you check the source of drivers installed in Windows 7 I think you will find many of them are from MSoft.
It is still a good idea to verify your system can handle Windows 7. Keep in mind that even if the hardware is compatible, the performance may not be acceptable.