Can't get computer to boot

I have a desktop that just had it's hard drive data transfered onto a new hard drive. After the guys did that, I got back the hard drive and the desktop and put in the hard drive (connected it to the SATA port) but I can't seem to get it to boot. It will do one of the following, seemingly randomly:
- Freeze at the HP/BIOS screen
- Tell me to insert boot media (something like that)
- Allow me to "Start Windows Normally" or "Enter Recovery Mode" but it just freezes at the Windows loading screen
- And just once I got an error that said "Windows failed to start - File: \Boot\BCD - Status: 0xc000000e - Info: An error occured while attempting to read boot config data"

I've tried reseating RAM, using one RAM stick at a time, playing around with all the connections, reseating the CMOS, unplugging the disk drive, trying different SATA ports, trying a different SATA cable, just about everything but I can't seem to get it to work. Most of the time I can't even get into the BIOS options/boot menu. Any ideas on what the problem is? If it makes any difference, the hard drive contents can be erased provided I'm able to install Windows again (I have a spare Windows 8 key and I can get Windows 7 if I have to - to install 8).

Thanks