GHO is an image of Hard Drive or one of HD partitions, made with Norton Ghost.
Norton Ghost is a "GLOCK" of disk imaging software. It will work every time where others may fail. Ultimate reliability.
Now, if you have a GHO file that I am guessing someone prepared for you when installing your windows, this is the best that you could hope for. Retain that tech, and tip him heavily.
With this file, you only need to procure a Ghost Boot Disc to be able to restore your windows to it's brand new state should you ever be in need of reinstall, and it will take you, oh, about 2 minutes.
I would not burn it to a CD, because Ghost will complain that the disc wasn't created by Ghost. There is a way to do it, but more complicated and frankly, why?
If you restore from a gho file residing on a hard drive, it is going to go very fast, and likely there will be no errors. (CDs and DVDs decay very quickly). If you need the space, just copy off the file to a hard drive that you just keep on the shelf, untill you need it.
Lastly, when and if you ever have to restore from that file, make sure that there are only two hard drives in the system, the one with the ghost file (the source) and the drive to be restored (the destination), because Ghost is very tough but UNFORGIVING. If you make a confused wrong selection, it will overwrite the wrong hard drive!
A ghost file can load windows on any computer if that is an image of Windows2000, and on exactly same hardware if it is the image of Windows XP. Substitution is possible but not easy.