If your computer is connected via wireless connection, you could have interference for somewhere (ie. 2.4Ghz cordless phone) This could cause the your computer to time out whenever you try to do something or just cause you to not be able to see anything on the network, even though it connects, seemingly without a problem.
If you have a wired connection, one of the most common problems I've seen is that the network cable is not made properly, it's common to make a cable to run from 1 room to another and a lot of people tend to group all the colored wires together, but this will cause them to interfere with each other. there are several sites with information on how to properly make Ethernet cable here's one with a helpful diagram http://geeksaresexy.blogspot.com/2006/01/s...e-your-own.html
Of course there are several other things that could cause these problems but these are the most common things I find so try it and see if it works.
The speed of sound is defined by the distance from door to computer divided by the time interval needed to close the media player and pull up your pants when your mom shouts "OH MY GOD WHAT ARE YOU DOING!!!"