IBM Thinkpad T20 won't boot or install a new OS

The computer originally had Windows 98 installed on it, but when booting it would give a blue screen of death. I've tried a number of things to try and get this laptop working again:

1. I tried reinstalling Windows 98 since I have the original official disk, after the install and reboot the system displayed the error: "Invalid system disk Replace the disk, and then press any key" I don't know what it means by "system disk"

2. I tried installing Devuan daedalus, the last 32 bit version of the operating system. It failed.

3. I tried installing a really old Linux, Fedora 3. The installer ran successfully enough that the hard drive partitions and names appear on other Linux environments, but the system shows the error "Operating System not found"

4. I booted up TinyCore linux, which successfully runs as a live environment from RAM. It was the one that detected the previous partitions created by the Fedora installer. It also cannot install onto the hard drive (some USB error? I'm using DVD so idk what that's about). I ran fsck successfully once, it told me the hard drive is dos paritioned. So fdisk -l detects Linux partitions, fsck detects dos, what is going on?

5. I tried SystemRescueCD, which crashed with a kernel panic.

Is anyone familiar with the ins and outs of an IBM Thinkpad T20? Does anyone know what the "Invalid system disk" error is about, it does not show up in any user manuals I found online. Does anyone know how to get any operating system working on one of these, or a way I can atleast definitively diagnose the issue?