IF you install it over the WIndows partitions then YES. You can try Linux without installing it by using any of the "Live CD" isks availabel for most of the distrubitions. Check out Fedora or Ubunto as they both have a cd you can boot from that will let you play with linux without changing your windows system.
Windows generally utilizes the entire disc when installed. In such a case, you either need to reduce the size of the C: drive first but since that usually is not a good idea, I recommend that you install Linux in a virtual machine, or install Ubuntu using their Windows installer. In the first case, you can run Windows and Linux at the same time (I do this on my work laptop). In the second case, you will have a dual-boot system, but the Linux data will be stored in a virtual disc that is a file in the Windows file system, and therefor capable of being backed up with normal Windows backup tools. Either approach may work well for you.