wininit.exe file missing from HD, now won't work?

[murph]

I bought my son a new HD as he screwed up his old one trying to delete a bunch of stuff thinking he was cleaning his system as it was freezing etc.....

Anyway, I want to get this old one running again. It's a 20gig WD with Windows ME. I plugged it into my machine and it's detected and starts etc but into a kind of safe mode looking screen with very limited functions, i.e. no mouse and there is almost nothing it allows you to do, basic display etc. After doing some snooping I found out that I THINK the problem is that he accidentally deleted the wininit.exe file...at least I am getting a message that all kinds of stuff cannot be done as this file is missing.

What the heck do I do? The drive still is good and he was ready to trash it but I don't know how to fix it. We have only a Windows ME upgrade disk which we used to upgrade from win98 which came with the system.

Can I link his hd to mine and copy stuff over?
Can I format this Hd and start fresh, and if so, how?
Any suggestions???