1. If you just wanted to switch to Linux, you would wipe the disk. You could share a Windows drive with Linux. Other (dual boot) options are sharing a drive with Windows and using separate hard disks for each operation system.

The installation procedure should be able to do all of the above for you.

2. Linux comes bundled with a number of drivers and many printers and scanners with work out If the box with no extra driver installations necessary. A couple of resources that may help you are OpenPrinting.org and Sane scanners. A bit of googling may also help you find out if anyone else has your device working under Linux