Uninstallation help

[bosKo]

a while ago i installed Red Hat onto an old IBM Aptiva we had lying around, it was either v6.1 or v7.0 that i installed, but i'm fairly sure it was v6.1   dad decided he wanted the computer back so I tried uninstalling linux, but it stuffed up somehow and now the computer boots asking for a disk.. but god knows what disk.  I've tried the boot disk that comes with the Aptiva, and its recovery disk.. neither work.   I rang IBM and they said I needed to get an "uninstall boot-disk for linux" or whatever he meant by that.   Does anyone have any ideas as to what I can do to get the computer working again because I'm stumped.