Hard Drive Recovery

My parents had a problem with the hard drive, it wasn’t booting, so I sys’d the drive with a Win95a Recovery disk from another PC. Now the hard drive is booting and loading windows but has the error
“This version of windows cannot run on MSDos version 7.0 or earlier”. Now I’m thinking that the sys didn’t help and now I’m hindered from actually fixing this hard drive becuase of this error. Is there a way to unsys a drive and bring it back to the original sys? Let me know….

Thanks

NE