Hi Rohmor, and welcome to our forums.
Sorry to hear of the problems you are experiencing.... it looks like you are between a rock and hard place...
Some thoughts for you.
1 When replacing a motherboard it is sound practice to reinstall your operating system. Even if the replacement is a like for like replacement there are often differences in manufacturing that create problems if the OS is not installed afresh. The differences may be slight but can be sufficient to cause the problems you are having.
2 Its not clear from your post if you are now trying to boot from your SSD ( Solid State Device) or your other hard drive ( a "spinner") but presumably from the SSD as that is likely to be considerably quicker than your spinner.
3 I would be inclined to remove one of the drives and concentrate on getting one of them to boot satisfactorily, with a fresh install of windows if necessary.
4 Once its booting up OK then you could copy across your data files from your back ups (that hopefully you have virus checked thoroughly using another machine that is known to be virus free and unlike XP that can safely be used whilst not isolated from other machines, sources of data, or the Internet.
5 Once all is well again and you have a servicable operating system with applications installed and virus free data copied across, you an then make a disc image (or several) with one at least kept safe on removable media offiste so in the event of further trouble with software/operating system you can be quickly up and running again with a re-image.
6 It is no longer safe, of course (since Microsoft stopped issueing most security updates) to run a computer with XP unless extraordinary precautions are taken, and the machine completely isolated from the internet and other sources of data.
Hope these thoughts help