I think I've resolved the problem with Zoom Modemm/Routers and Windows 7 connectivity.
A previous discussion in this forum could not remember the solution proposed by others. This seemed like a DSL service error, but extensive discussions and tests with AT&T seemed to indicate that there was no problem with the service.
One solution I ran into was the suggestion that malware/spyware had infected the computer. The Router's log was showing time out messages. I had a similar problem that appeared one day and it perplexed me. It took me a while to decide that looking at the log file might provide a clue.
The situation was that I had a computer that was behaving differently in two different wifi locations that I had setup. In both locations, a primary router was connected to the internet and a Netgear wireless router was connected to the primary router.
In location 1, the primary router was supplied by RCN. In location 2, I had replaced an AT&T router (failure) with the Zoom ADSL X6. The two Netgear routers were configured pretty much the same.
So the main difference between the two locations was in the primary router that was connected to the internet.
In location 1, several computers worked fine (2 WINXP, 1 Windows 7).
In location 2, the XP computers worked fine, but the Windows 7 computer's wifi showed that there was "no internet connectivity".
The fact that the Windows 7 machine worked in one location, but not at the other was indicative that the computer's wireless card was not the problem. The card was able to connect through an AIR CARD in both locations (bypassing the wifi), so the problem had to be elsewhere.
So since the only hardware difference between the two locations was the primary router, the Zoom was the most likely source of the problem.
That's when I looked at the Zoom router's log file and found the "time out" messages (among other suspicious ones).
Internet searches finally took me to answers.com (yahoo) where I found a query about this exact Zoom router with the log file printed out. The "best answer" was that some malware/trojan had infected the computer and the suggestion was to run the Malwarebytes program.
I've run this program successfully on other computers (XP) and it was very good at finding issues and removing problems. However Malwarebytes found nothing on the Windows 7 machine.
I usually look for multiple solutions and this seemed like a good time to also run Spybot. This program found several hundred issues and fixed them. After running Spybot, the ADSL X6 router started working again, as the log file showed no more time out errors.
So it seems as though someone very clever has written malware/spyware to trick a Zoom router (perhaps others) into misbehaving. This code specifically affected a Zoom router (in location 1) but the RCN router (location 2) was not affected.
The lesson here is that malware often tricks us into thinking that we have a hardware problem or that there is a connectivity problem, and that's the goal of malware/spyware - to trick us into looking for and applying the wrong solution.
In this case, there was nothing electronically wrong with the Zoom router.
We have to think outside of the box at times to realize that one person's solution may not be the big picture answer. Malwarebytes worked for one person and not for me. Spybot worked for me but who knows what other malware/spyware will do whether that program alone will work for someone else.
Other software defenses to situations like this include Microsoft Essentials (found nothing) and AVIRA Anti Virus (didn't run this on Windows 7 yet).
I've found that these 4 programs have worked well for me over the years. If you find others solutions to similar problems, please respond to this post on this forum so that I and others will keep up to date with new solutions.
I hope this helps others.