TechSpot posted a guide about removing your Windows 7 installation
>> Removing your Windows 7 installation, partition
The strongest critique we received about our recent guide on dual booting Windows 7 with XP/Vista was that we should've included information covering the likely event of you wanting to kick the beta OS to the curb, sooner or later.
Well, we couldn't agree more, so as a follow up to that guide we're going to look at the reverse process; deleting your Windows 7 partition and reallocating its hard drive space to another partition.
>> Removing your Windows 7 installation, partition