Very sagging windows and word8

Recently I had to upgrade 3 Dell 133 pentium maskines from win95 to win98. Mostly because of the USB rutines. After that, the maskines are very slow, some(quite big, c:a 400k) Word8 files wont even start, they hang the maskine completely. The maskines have 96 Mb ram, so that`s not the problem, and the program doesnt swap to the disk.
Sholdn`t 133 pentium maskines upgrade to win98? Or is there another answer to the sagging?