For some reason it is boot cycling witch means something in the hardware side in not right... Try booting it without anything not needed to boot like the HDD, wifi card and such, this is hard to diagnose in laptops but you have to find out what is wrong by the prossesser of elimination (that is why it is hard to do with a laptop, most of it can't be take out) there is a good chance you may not be able to fix it and will have to get a new computer but on the bright side it looks like the HDD is OK as you said it worked in another machine so... All the stuffs is still there...