Sounds like the software merely did something to your hard drive to make it non-bootable, or hang (maybe corrupted the boot sector).
Don't go buying new hardware when it probably is a fairly easy fix.
At worst you'll have to re-format your hard drive and re-install Workbench and everything from scratch (but mostly likely you'll be able to salvage or repair the filesystem, as others have said, with software).
I don't think it's possible for the mystery disk to have physically damaged the hardware.
