Booting by floppy trying to keep data on HD

[maddogfighterac]

having deleted system files. Yes i know so much. I now find the dude who said he'd fix my computer(5 mths ago) has gone to Norway!
So i have to fix it myself
Away, it can''t find the CD-ROM so i got a wind98 boot disk. But it won't work as. The message says that its can't install due to compression software on the harddisk.
Oh did i say i want to keep the data on the harddisk.
I don't want to move the disk from another machine as this seems like a problem i'd like to know how to solve.
please help someone