Clearing an old file server

I have an old Compaq Prosignia File Server that I need to erase all data on. The OS is Windows NT4. It also has Arcserve (think its a backup program). I cannot seem to get into it to erase all the data. I’ve tried booting up with the OS disc in, with a Kill Disk in etc, but this Arcserve program just kicks in every time. I cannot even get into the BIOS to ask it to change the boot sequence. I don’t mind if the whole thing is wiped so that I have to reinstall the OS – I can’t even throw it out until the data is all reased. Thanks very much for any help anyone can give me.