You don't need to reformat, Or Recover the Data, when you swap a main component such as the motherboard, Boot off of your Windows XP Disc, Tell it to install, it Will Detect a previous installation, it will then give you the option to Repair. Hit R to run a repair Install, You should then be able to boot after restart.
As for your other problem, Its possible that The New Motherboard is grounding out a the Case or another metal Object within the Case.
Therefore Try Posting without the Case, with everything connected place the motherboard on a Hard Non-Conductive Surface and turn it on. Post back with results.