Can you wall paper over a wall that has been painted over the original paper
You can as long as its in reasonable condition although it would be better to steam the old paper off.
To get a better finish and eliminate any risk of it going wrong it would be best to remove old wallpaper first
depends on the type of paint, i would sugest a watered down thin layer of pva glue first
Its not a good idea to paper over any existing wallpaper let alone a painted wallpaper as the finish and seems can never be tidy and will quite easily attract air bubbles and the old paper my become saturated with the new paste it begins to lift.
You can, and can make the wall paper behind bubble or lift. Ideally would be more suitable and recommend taking the wall paper off and cross lining first and then putting your main wall paper on top.
It would all depend what type of paper the original paper was, if it is just lining paper, you can (although ideally you should always completely strip walls and begin again).
FOR A BEST FINISH YOU NEED TO TAKE OF THE OLD WALL PAPER .
BUT IF THE PAPER IS LINED PAPER AND IN GOOD SURFACE IS POSSIBLE.
If the paint is in good condition thats ok
Not recommended. Strip old paper first.
It can be papered but you cannot guarantee you won't get any bubbles from original paper.
You can but it wouldn't last long it would start peeling away unless u put an oil based primer on first
Your better off removing old paper, as once new paper is put up it may raise due to the moisture from paste and the end result may not look great
It's a hard one, it really should be striped and repaperd, but if an adhesive was previously used. Or the paper is still stuck very well then painted over it should be OK. But you would want to give the wall a good look over for any lifting paper and repair with adhesive. It all needs to be bonded really well for it to be paper over or the extra weight could peel the underlying paper.
In this situation it would be best to strip original paper
Yes you should be able to
Yes you can, however I would follow the following procedure.
Apply wall putty to any cracks or holes in the wall with a putty knife, then wait for it to dry. Afterward, sand it smooth with fine-grit sandpaper. Prime the walls with a stain killer/primer. Paint the primer on evenly with a brush before you install wallpaper