Re: Software Legallity?
If you still own a copy of Windows, it is yours to do what you'd like with. Legally, if you install it on your new system, you must uninstall it from your old system.
Also, just for clarification, when you say 'software data CD', what do you mean? If you mean restore discs, those are almost guaranteed not to work in another computer. They're made to work only with that brand. If it's the Windows installer disc though, it should work fine.