to ask permission we can use the following expressions.

neutral:
may l use your computer?
can l use your computer pleas?
could l use your computer/?
do you mind if l use your computer?
informal:
let me use your computer, would you?
ok, if l  usse your computer?
let me use your computer, would you?
formal:
can l have your permission to use your computer?
do you have any objections if l open the door?

neutra;
well, because my computer is out of order.
well, you can see any computer is out of order.
let me explain. you see my computer is aout of order.
informal:
welll, the thing is my computer is out of order.
it's  like this, you see my computer is out of order
formal:
the main reason is that my computer is out of order.
if l could explain, my computer is out of order.