xp just can’t start and cannot be formatted?

my comp. got some errors like 135 registry prob and b4 that someone managed to help me to format my comp. but it got stuck for 4 hrs at stage 4 of 5 during the procedure? so i just restart my comp hopin to format it again. and i thot everything was fine but im wrong. i manage to get in the desktop but only once. now whenever i start up it just pop out a black screen indicating what “power failure like inproper shutdown” and leaving me choices to enter thru’ safe mode or normal, etc.. i tried safe mode & normal & last gd configuration but it load halfway (at the xp blue bar loading) and it reboot itself leaving me back to that black screen again.. (i have tried MANY times) i wish to know wat/how to do abt it.. my comp. used to run fast but now the startup/loading is slow.. is there some cause? i have 2 hard drives..

can someone help?