Swap Hard Drives

[matrix3]

I bought a Windows 10 pc as it had better specs than my old Windows 7 one which still works. I installed the Windows 7 hard drive into the new pc after disconnecting the SATA and power cables from the main hard drive and connecting them to old one. My plan is to use the Windows 7 hard drive as the main one as I prefer it over Windows 10 and have the Windows 7 boot disk to reinstall it. However when I boot the new pc it tells me to “Reboot and Select proper Boot device or Insert Boot Media in selected Boot device”. I reconnected the Windows 10 hard drive and returned the Windows 7 back to the old pc and they both boot up perfectly. What I am doing wrong? Any advice would be appreciated.

 

[wpgwpg]

Swapping drives with Windows installed between two PCs can get you into trouble. The Windows install process tailors what's installed to the particular configuration it runs on, and when you swap to another PC, that customization is no longer valid. Sometimes folks do it and get away with it, but it's much better to do a fresh clean install to avoid problems. A little more work but a lot better results this way.

 

[USAFRet]

System A, Drive B, OS C
System X, Drive Y, OS Z


Switch them around, and not booting up is often the result.

The only thing you're doing wrong is assuming they would just boot up.

 

[matrix3]

So I should delete Windows 7 and reinstall it using the boot disk?

 

[USAFRet]

So I should delete Windows 7 and reinstall it using the boot disk?

That depends on what you want the end state of this to be.
Which OS on which drive and system.

Also, is your Win 7 license able to be moved to different hardware? Not all can.