SRS, depending on how long the noncommunicative computer will be left intact, you have a couple of options.
You can take the hard drive from that one and put it into an external hard drive case to be used as an auxiliary for the other computer.
You can transfer the data via thumb drive.
If you have a Windows 7 key for the one that's not happy, you can put another hard drive in that machine and use the Win 7 key with a freshly downloaded version of Win 10. That may also fix the communication problem [No guarantee, tho.]