Problems when updating my kernel !

Hi ! When I installed a new kernel (from MAntel, 2.4.18-135), I got a very nasty problem ! When I did a make modules-install, the new kernel overwrote my old kernel. Now when I am booting from the old (or new) kernel, I got an error : The system locked at the module : hotplug ide-scsi. Very nasty, I am able to boot the safe module but I am wondering how can I get back my old system. The initrd and vmlinuz were overwritten. It is very sad to see that the kernel overwrote something without asking me an authorization. Could you help me please, I have a floppy disk with the old system inside, maybe it is possible to restore the old system whithout reinstalling everything ! Arnaud