With most installers for linux you will have to format the drive and partition it during the installation process, linux has its own hard drive formats and does not use those of windoze.
Having just had to install drivers for my ADSL modem I can tell you that it
can be a complete pain.
However there are companies that distribute linux drivers for their products. First port of call is to find the manufacturers of your modem on the web and check for drivers there. If not, check to see if there are any open source drivers for the product, for instance surf to
http://sourceforge.net/.
Failing that you will probably have to get new hardware.
Some of the more commercial distributions, redhat for instance, include drivers for a wide range of hardware. Check out the different distributions and pick the one that is going to work best for you. Check out
http://www.distrowatch.com/ as a starting point.
If you are willing to get stuck in and get your hands dirty there are solutions out there, you will also get to understand your computer and how it works better.