Can't be done - not without weeks of work, I'd say. The drivers installed with your laptop will be so very different from those needed by the desktop, that it'll fail.
You can, of course, run the normal hard drive of the desktop and access infromation on the laptop harddrive, but not run the applications.
Having said all that, if you have cloned the drive, you can always give it a go - not much to lose, data-wise. Set the desktop to boot from the laptop drive (installed as a USB-connected hard drive), and run a repair install from the Windows disk. But, it won't work ;-)