The 2.6 kernel, which ships with Mandrake 10 as well as other new Linux releases like SuSE, Fedora Core etc does support the ATI Radeon 9600 graphics card.
However, the 2.4 kernel doesn't have support for your card, but if you want to get it working, you can download the driver from ATI and follow the instructions on how to install it.
Got no answers to your mousy problems, but check out this site to see if your winmodem has a driver for Linux.
Normally I advice people to use an external serial modem with Linux (Hayes Zoom have Linux support!) because 99% of them will work under Linux. With winmodems it depends on the chipset. In any case, it is a rather painful experience to try and configure a winmodem if no driver is supplied with your distro.