You have to reinstall all the programs if you go the Windows 10 route, and it could be some very old ones will not be compatible with Windows 10.
I’ve just had a thought.
If you still have your Windows 7 clone on the SSD. you could try the following.
1, Remove the SATA cables from all the HDD’s leaving only the SATA cable connected to the SSD, and DVD.
2.,Boot from your original Windows 7 install DVD or USB media.
3, Once booted into the Windows 7 install procedure, select the following.
3b, Select ‘repair my system or PC’.
3c, Select the option to diagnose ‘Problems preventing Windows from starting’ and follow the prompts.
This might put an active MBR onto the SSD and allow it to boot Windows 7.