check that the program is compatible with win xp
win xp has been unsupported for more than 10 years so many programs will not run in that operating system
Games, like MOHAA I think play good in windows 8.1 and windows 10 , I already prove it that. just, make sure the version of your OS, 32 bit, or 64bit. and just copy de MOHAA folder if you have a backup of your past OS eje: windows 7, justo copy the Mohaa folder. it should work.
Have fun!
Carl