Hi bros. for my hardware. i'm planning to upgrade it to windows 8.1, I just have few questions tho those who tried it already. first, do I have to re install my programs after upgrading? what about the files? and second..., does it ask for a serial number or activation code or alike? coz my laptop came without any disks, dvds etc, just a pre installed OS and acer apps. so I don't have a code. thanks