odd downloading problem

It is interesting to look at a few other threads on freezing, hanging etc.
may be related.....


Win7 HP Pavillion Laptop
Firefox Internet Download Manager

DSL from ATT Speedstream 5100 modem


normal download speed 3008 kbs/s

1) has worked well for about 6 months
2) many updates to all programs and win7 - later odd problem
3) does not appear to be ATT - techs have checked line and modem many times


description:

during downloads of a batch of files, downloads drop in speed then shut down to zero -- modem sometimes resets itself -- to a much slower speed.

does not "seem" to be a firewall problem - PC Internet Security Suite
and yes I hate to try there tech support for any answers...

OK - reboot modem many times -- no luck will not reset to normal speed.
power off modem and reboot computer -- sometimes will get proper speed.
hard reboot of laptop and reboot modem sometimes will get proper speed.
problem getting worse


suspicions are that there is a win7 app accessing the internet which blows away my downloads. -- but what? there is nothing showing in the task manager...
maybe win7 error reporting?


requests:

1) is there a program that will definitely show me what programs are accessing the internet in real time via any/all ports?
2) how can I turn off any possible win7 apps that may want to access the internet?
3) any clever ideas?

---- and yes, I have the latest updates to every driver win7 and HP recommended.

Yes the modem is older. The techs that have looked at it say it still works fine and has been updated late last year. ATT does not seem to be interested in replacing this thing.

Batch downloads do not impact my download speed because although my download connection is 3008 kb/s ATT throttles that back to actual system downloads of 350 kb/s at the DSL Hub. That prevents them from impacting sales of their cable systems

weather could be a factor from time to time - and Texas has had cooler than usual

--- but, I have been at this for some time with good results until a few months ago and the problem is getting worse. I think weather to be a very low likelyhood.

What I am trying to do is to isolate and identify. gor everything I can find turned off. troubleshooting intermittent problems is one of the hardest tasks around.

if, as I suspect, something from HP or MS is accessing the internet, I can't find it.

I do not believe it to be memory problem since I have more than 2.5 gig free.