Sadly, there is NO SUPPORTED or documented method to move working XP install from another partition to the boot partition. Also, no tool combines the partitions from Microsoft.

The "cheap" way out is to nstall a new boot drive, install XP, then use the Files and Settings Transfer wizard to move your files and settings.

You can also start off with the partition size you want.

And yes, there is partition magic, but a new drive is just as much money.