Help needed please regarding ghost 9.0 - cannot boot to by external HD copy

My internal OS was unrecoverable on a Compaq.  I'm getting basic internet access at least with a loaned internal HD that my neighbor installed with Linux on it, but I'm not savvy enough to continue with Linux long term.   I have a Ghost 9.0 copy of my old internal HD on an external, but I cannot boot to the external.  I can access the external and access my saved files thank god.

 

I read somewhere that Compaq uses a 240 pocket filing system and that new external HDs use 255 or something? Is this why I cannot boot to my external copied OS?  If I can somehow use the ghost disk to copy back my external HD to the original Compaq internal HD, will it work then or will it copy back an OS file format that is unrecognizable to the Compaq BIOS?

 

I've already checked with Compaq and they cannot get me a new boot disk for Windows XP because it is too old.

I'd prefer to save this desktop system with XP replenished, but at last resort I'd rather buy a new computer if I have to purchase a Windows 7 OS anyway.

 

Help to solve my Ghost copy boot issue or verification of my assumption that I may need to shell out for a new PC is appreciated.  :manfrustrated: