Upgradeing Question

This might be an obvious one.

I am preparing to upgrade my Motherboard/Chipset and GPU.

My questions are as follows:

Will this cause a need to reformat my hardrive?

If So, is there a way(software program) to back-up my hardrive so that I do not lose all the files I have? (i.e. some electronically downloaded software,pics,movies, and other file types)

ANy advice or directions to help would be greatly appreciated!

-J-