return to windows 98 from xp pro

confused

due to "illegal" product key code for my xp pro, it appears that the best way to go is to re-install the original windows 98 that came with my computer.
Before I re-format my hard drive, what about all the software programs, etc., that I am now enjoying using xp pro? What about any documents? Will any or all of these become inaccessable once I have windows 98 installed?
Any help would be appreciated. Thanks

 

If you don't copy them to external media when you format you will loose any and all programs/info and what not currently installed.