Speedstream 4200 i got a speedstream 4200 and it was working fine but now my internet is really slow and the ethernet light blinks like crazy.i dont know what to do and i really need my internet going again. please help me!!

Check all the cables and make sure that they are plugged in tightly. After that I can't help you without more information.

turn on the wireless option in the router...
plug your computer into the router type in
192.168.1.1
username: admin
Password: public

go to wireless tab
turn it on

END!
P.S.
Also you have to be in range!

My son went on the computer and reset the modem to the computer.

You can't use the Motorola SBG900 for that. The only way it might work is if the Motorola SBG900 had a 4-port Ethernet switch built into it.

Well, you are very correct with the activity light blinking and the increased blinking except the fact that modem will encounter a problem in future...
The 5 different lights on your modem namely Power, Ethernet, DSL, Internet and Activity have their own indications and explanations.
1. The Activity Light indicates the amount of activity that is takin place on the computer on the Internet though the activity might blink even when you are not browsing. This can be explained by stating that the computer constantly keep sending signals  about it being connected to the internet and any other acknowledgements..

So, you've got nothing worry about unless the Power or the Ethernet or the DSL or the Internet light Blinks....
Cause they are the resultants of a fried modem(check for the adapter), faulty LAN connections, interrupted Dsl line and the account verification failure indications respectively.....

Please check if the POWER light on your modem is solid RED.
Because if it is, your modem is already defective.
If you purchased it from your Internet Service Provider,contact them to check if your modem is still in warranty so they can replace it ot not.
If you purchased it from near computer shops near you, they it's time to buy a new modem.

You need ethernet for this. No router I have seen in all my years of networking will accept a USB plug

Unfortunately it sounds like the modem may need to be replaced. I had the same issue. Even after doing a complete shutdown, resetting all the cables, restarting the modem and then the computer, it still did not work. After you get the modem replaced, I would suggest you get a spare, possibably from e-bay, so if this happens again, you will not be without DSL Service.

I have just set up 4200 with dsl - you may find that you need to reset modem before you can configure. I was told that you need either a grey or yellow cable from your laptop to the modem. I use 10.0.0.138 to access modem. The 4200 I have was from a bigpond a/c - originally configured accordingly.
Regards,
Richard

OK, we are all not dumb. the question is where are the drivers. Just go to www.hankscomputerservice.com/SpeedStream4200driversxp&vista.zip for both the drivers for XP & VISTA, or get everything ells you want from http://www.thevoipstore.net/speedstream-4200.php