HP g4 laptop that came with Win8 won't recognize Win7 on a different hard drive?

Phil3525

Honorable
Dec 29, 2013
7
0
10,510
I bought an HP g4-2320 used to replace my daughter's g4-1015 that had a mobo failure. The 2320 originally came with Win8 installed, but the previous owner kept the original hard drive. I transferred the hard drive from the 1015 to the 2320, but the 2320 bios will not recognize the factory-installed version of Win7 that's on her hard drive. What do I need to do toget the 2320 to recognize the Win7 OS on her drive?