"Select propper boot device" after removing old hard drive and trying

I have recently bought a new hard drive and now I want to remove the old one and just use the new one.
When I remove the old one, I try to start up the PC with the new only, but it stucks at booting, it says "select proper boot device..."

The old one was a 300 GB, WD SATA 2. And the new one is a Seagate SATA 3 1TB. I want to use the old one with an older PC for somebody else, but if I remove it I can't get into Windows.

Windows 7 is installed in the new HDD. The old one is empty, but I see there is still some "System Reserved" partition there which is being used. Here is how disk management looks like: https://i.imgur.com/Gsbh3dF.png
I want to remove Disk 0 and keep Disk 1 only. I also don't want to lose the data from Disk 1.

Help will be much apreciated. I try to rebuild my old computer for somebody else to use.

System reserved partition is essential for Windows to work.Since you have it on your old hard drive and not the new one ,computer asks for it whenever you disconnect your old hdd.
Install Windows on new hard drive with system reserved partition on new hdd.