Can anybody help?

As I have said before on other thread, my darling 14 yr old son has broken two of the USB ports on my computer by shoving his web-cam in rather roughly to say the least Anyway we just have one port now at the back of the tower so we bought a USB Connection thingy that allows you to run 4 things off one port. We got it from argos for £14.99 and it worked for about 3 times and then when I plugged my camera into it (although it was fine the first 3 times) one day it wouldn't work so we assumed that it must have a breakage in the wire or something because it was only a little thin wire.

Anyway we then bought a better one from Currys which was £34.99 and it has 4 ports running off the one port at the back of the tower but the wire is like a thick cable so we thought this would work fine. It even plugs in to make sure that the electricity is divided equally into the ports or something like that. Anyway the same again, it worked for precisely three or 4 times and now when I plug my camera in it won't work again We have checked that the device is plugged in properly at the back and the same when we used the other one so anybody any ideas why this is happening

The hub might not be powerfull enough to run the camera , mine isn't -I have to plug the camera straight into the back of the pc -If its not working at all then I'd disconnect it -turn the pc off -back on and then plug the hub in again
hth
Liz

Oh I see I never realised that I thought that the hub was just like an extension on the original port and you are meant to be able to run four separate things from it all at the same time and we are only trying to run one It worked fine the first few times though so I just can't understand why it won't now