Computer上網問題......

I am not sure where are you using your computer internet services.

But one of the most probable reasons is because your internet provider has blocked
the websites.

One of the easiest methods is the try to use secured connection to try to skip the
block by "https" (e.g. https://facebook.com)

You may also use proxy, ultrasurf is one of the best proxy software.

//Is there any enquires, please feel free to send an email to me.

youtube都係google，點會上唔倒﹖就算你打錯字都上到。