Hi there and welcome
The best method is to use a USB Drive or memory stick, you can then copy your personal files to it so there is a copy of them off the computer.
this film will show you how to do this.
Once done, you can then do the upgrade and if anything goes wrong, you have a copy of your files safely stored on your USB drive or memory stick.
If you would like any additional information or assistance, please do not hesitate to let me know.
Else if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.