On a lot of Windows based test gear, there can be a ghost backup file on the HDD that was put there by the manufacturer. This allows a full factory restore if you keep a copy of this file. It's best to back all this stuff up including any calibration files. I've got several Windows based instruments here and that's what I have done with all of them. Back up the HDD and keep the instruments away from a network and I don't think there is much of a downside to having a Windows OS. I generally prefer using Windows based instruments.?
In my experience, it's usually the switch mode PSU or some RF MMIC device or something to do with an LO synthesiser that causes failures in 10-20 year old RF test gear from the big name companies.
