i dont think its the HDD because when i put it in another computer it boots up fine.
This wouldn't be the computer that HDD came out of would it?
yeah actually, this computer is really old (uses IDE connectors) and the cd drives weren't working so i took the hard drive out and installed the OS on a different PC; I was told this wouldn't be a problem though.
It is a problem since the drivers will not match your new hardware.
You were told wrong. When windows was installed, it installed all the drivers for the other motherboard and devices. When you move it over to the machine you want to use, none of the drivers are matching.
You can try booting into safe mode and deleting the IDE controllers and other system drivers. That might get you back up. Why don't the optical drives work?