Hello Shiho, welcome to SF!
A question to see if I understand correctly...
You FIRST bought it with operating system??? It is not clear. I'm guessing you did not buy it with windows8 on it
You then installed Windows 7 which gave problems?
And then Windows8, which is what you are using now??
As the upload of info is very limited it is hard to say what to do next.
From that upload, it is clear that you miss multiple device drivers and need to do a checkdisk on your HDD.
But IF I understand your story correctly... I'd do a clean install.