There could be a number things at play here. But it is strange your not getting any errors.

Maybe you need to explain how you hooked up the two hard disk and performed the disk images, and whether you have had the two disks connected at the same whilist windows was up and running. That is, there is an entry within the registry about what volume a specific disk (signature) should be mounted as.

Also, please confirm that we're talking about VIsta, which version it is, and that the 40GB still works on the laptop.

I'm thinking that you might be doing something naughty like running an OEM specific version on the wrong brand of laptop... [A]