Steam games migration
Steam games migration
Place your 'my games' folder in your documents, check for other game folders there, and also copy the Steam folder. After installing the new OS, combine 'my games' with the previous version, move the Steam folder elsewhere, remove the clientregistry.blob file in the Steam directory, then launch Steam and it should function properly.
Yes, you can. Game saves are usually kept in the documents folder or a hidden appdata folder (such as in Minecraft), so you should check both and back them up.
No need to change the Steam folder unless you have specific reasons.