When I was still living in Egypt I came across some cool programs that can freak people out Just as a joke but it did not cause any harm to pcs , one of these programs was a program that changes the back ground to an ugly old witch or some thing. So I think if your computer changes its back ground May be you have got a Trojan or some malicious software that changes your settings and issue commands to your computer. I would think of may be some user scheduled that to happen in your PC i do not know if it is possible using windows task scheduler. which can make a computer come back from hibernation and run some programs like AV s. To fix such a problem You got two good options and have effective results. The first one is to run an updated anti Virus full system scanning spy ware add-ware software, Then create a restore point use windows defender to scan your system. The second one is to re install the operating system and I would Recommend Vista but with this option you will need to back up all your data to an external medium such as am external hard drive, or write your data to a DVD or flash drive.
morphing
Chemical change
No, you do not have to reset the computer. It will take care of itself.
Not necessary. The computer will reset itself after a few driving cycles.
No, it will take care of itself.
You do not have to reset the computer any more than you reset your computer in your home after a power outage. It will take care of itself.
You do not have to reset the computer after this repair. If the Check Engine Light is on it is not because you made this repair. If you disconnected the battery the computer will reset itself.
Changing the battery will not make the light come on. The computer will automatically recalibrate itself after a few driving cycles. If the check engine light is on, you have a problem with the emissions system. Have the computer scanned with an OBD2 scan tool.
aging
Phases.
Format
There's all sorts of things you can do to personalise your computer... From changing the picture Windows displays when you log-on - to the wallpaper, the theme, sounds and general appearance. They're all changeable by the user.