Is windows 98 c0mpatible with windows 7

i work on four pcs, one with windows 98, one with xp, an old laptop with 98 and a newish laptop with vista. i also have the disc for converting vista to windows 7.
at present at the end of each working day i transfer all files worked on among all four as a security measure, between the two 98s and vista on an intranet, and from that to the newish laptop via memory stick. this goes swimmingly and is absolutely reliable, which is essential as i have 38 years of research onboard. will that still be the case if i convert vista to windows7?