LAN sometimes works..

I am using Windows 7 Home Premium Service Pack 1 (64-bit)

I just formatted my laptop because I thought it was virus at first. But the internet still isn't working. I tried with a different laptop on the same connection and it works perfectly fine. So, I am pretty convinced it's my laptop's problem?

NOTE: this is a clean copy after I restored to factory settings. It may be some old internet settings remained the same? I don't know about that.

Problem : My internet sometimes work and sometimes just completely stopped working. I live in a flat and basically, what I usually need to do is connect the ethernet cable to the socket and it will just work normally. Now that the problem occured, when I looked at the Network Map of LAN. It shows that I am connected to a switch along with different users? Then, through a gateway to the internet? I've attached two screenshots to help understand my situation.

Could someone help me with this matter, please? I am pretty stucked and haven't got a single clue how to solve this 'funny' problem.

Enclosed is two figures:
1. Completely not working when the first figure mapping shows
2. sometimes works but sometimes don't when the second figure mapping shows

Many thanks
JC