I need help to fix a severe registry problem?

My Home Pc is running Win xp Home. it is an OEM from Dixons and unfortunatly i seem unable to get a copy of the Disk from Source. Following a series of Blue Screens (varied Errors without any apparent solution) my PC essentially gave up booting altogether. There was a message that flashed up saying "missing Registry file" and "System 32". I panicked somewhat and because i couldnt boot into the Hard drive, I used a smaller Hard Disk that had Win XP Pro on it and used that as the OS which enabled me to at least access all my documents and photos. However i cannot get the Original HD to boot up i have no way of knowing which registry file is missing. is there a printable list of the file names that should be in System 32 or someway of locating the missing file and copying it from xp pro. I know it is a bit involved but i am tearing my ramaining hair out and this place has been helpful before