Sorry to interupt and add my two cents worth;
But I wanted SAGERAZIEL to know that I agree with JASON2074.
SAGERAZIEL; your older computer (that you recently brought back into service) probably did not have all the current updates loaded on it (SP2 or SP3). Perhaps it had NOT even (never) been configured to work on this local router?
But, as JASON said, you should have been able to plug the ethernet cord into that old computer, and into the router to establish internet connectivity. It does have an ethernet port in it, doesn't it?
Now here are some basic facts:
1. that USB CABLE connector is only going to give you a 10MB connection speed between the Router and that computer.
2. The ETHERNET (wired) cable will allow a 100MB connection speed between the router and the computer.
3. The WIRELESS connection's maximum connection speed is 54MB. (Many times it is even slower)
Think of these connection speeds like driving speeds (MB=MPH) and you might understand this easier.
Do you want to "drive down" the information highway at 10mph, 54mph, or 100mph?
Are you still with me? These are just the connection speeds to connect EACH COMPUTER to the ROUTER.
YES; they can all be going at different SPEEDS as they connect into your ROUTER.
Your ROUTER is then connected to the DSL Modem or CABLE modem. Think of your ROUTER as a FUNNEL.
All your computers (whether Ethernet, USB, or Wireless -at different speeds- are all funnelled together into that ONE CABLE/DSL MODEM.
What speed did your cable company tell you that you have coming into the house?
Is it the cheap/easy/basic 1.5MB speed? Did you upgrade to the 3MB. 6MB, or 12MB speed?
YES, they charge more for faster connections!
JASON2074 was correct to tell you to get rid of the USB cable. That is ancient technology (at least 10+ years old).
YOU were correct that powering down your old computer allowed the other computers to connect at a faster speed.
(again; think of the funnel. Or think of the slow folks in front of you as you merge onto the freeway each morning)
Am I making any sense for you?
Hopefully, I was able to explain this in a manner that informed you without insulting you.
Best regards in your future computing,
Sleepyjohn