All your pinyin are right, but please notice this one:
你用你的电脑还是手机上网?
Ni yong ni de dian nao hai shi shou ji shang wang?
Are you using your computer or your mobile to go online?
We often say"你用电脑还是手机上网?" just delete “你的” shall be OK~
another example:
“你开车去上班还是走路去?”and “你开车还是走路去上班?” both right centences.
“你开你的车去上班还是走路去?”this one is wrong.