First off, disconnect all those switches and PCs and simplify the equipment to it's most basic set up, a PC hooked to their modem with the router and switched eliminated. You should just be able to reboot the PC and connect to the Internet. Can you connect to the internet? If not, you might have to flush out some garbage that has gummed up the works because of all the messing around you've been doing. To ungum it, do this:

At the command prompt type:

ipconfig /flushdns [hit enter]
ipconfig /release [hit enter]
ipconfig /renew [hit enter]

Now try your browser again with only the PC connected to the modem. Now can you connect to the internet?

If not, you may want to repeat the entire above process with a different PC or a laptop that you know has a good network card, so you can eliminate the possibility the PC you are using has a bad network card.

If you still cannot connect after trying two different PCs, and after flushing the IP caches, then the problem is most likely on their end, or the modem they sent you is bad. Call the Helpdesk Moron and ask him to send a ping command to your modem's ip address. At the same time, send a ping command to it from your command prompt. If he can ping it, and you can't, or vice versa, he's got work to do. Usually, if he can ping it and you can't, the modem is bad, and I see that all the time. Have them ship you a new modem. If he can't ping it, then they've messed up somewhere in their software setup of your account. Again, make sure you have your connections totally simplified before doing this test with the Helpdesk - don't hook all that other garbage up until you have verified you've got surf.

If you can connect to the Internet with only your PC connected, then you have proved that the connection from the ISP is not the problem, which means your router is configured wrong or is bad, or one of those switches or network cards in one of the other PC's is bad and is causing the whole network to malfunction.