lost files, windows 98 cannot start

recently some how i lost some very crucial files that run my operating system, which is windows 98. these files are wiped clean off my hard drive. i have tried every way possible to restore these missing flles but they are just gone. i have a windows 98 installation cd, but it only gets to 20% and i recieve an error message telling me i have interrupted set up and it cannot continue to copy files. apparently my hard drive does not have enough space to run this set up. is ther any way that i can down load a set up program to a floppy disk, and run set up from drive A? im not Eienstien, but im not a dumb dumb either. can someone help me in the easiest way possible? please!