Windows Forensics Software

I know the machines have been hacked, but I need to know who, what, when, and to LOCK them down!!
How do you know that they have been hacked if you don't know what has been done to them?

Here are some lock down application that I have used with various companies.
Fortres 101 (http://www.fortresgrand.com/products/fortres_101.htm)
Clean Slate (http://www.fortresgrand.com/products/cleanslate.htm)

So the "hackers" told on themselves? Since that is how you know, that is pretty much your only true avenue to find out what was done.

They told me they have been on the box and know others have been too, but will not tell me what they did or where.
Sounds like wanting attention and talk to me. A hacker doesn't tell on himself/herself just to brag.

Anyway, I have never seen any software that does what you want. As I already posted, there are lockout programs.

Concerning how to find out what was done, run spyware and virus scans. Also make sure you check the running processes and startup items.