Switch-Accessing Online Games Problem

I got a switch today which is like a router but no encryption etc (since it's 70+ dollars cheaper than a router). I connected both computers to the internet... the internet's working awesome (probably even better than before) and both computers are connecting nicely.... one computer is a HP (two weeks old) the other is a Cicero (but it rocks even better than the HP and it is 4 years old oO)

Now I did a IP check and they were different.... the last 6 numbers were completely different... but here's the problem... whenever I try to log into an online game the HP computer connects, but the Cicero computer doesn't connect for some reason. Now I'm not sure if it's an IP problem or if it's just the computer problem? But for some reason I think it has to do with the switch.... can anyone advice me on this one?

I mean I would understand if they don't let me connect since we got the same IP... but apparently that's not the case...

Jam it back in, in the dark.