This matter appears to be resolved:
It appears the problem was something that went wrong inside the belly of the virtually new, two month old ATT modem.
I hope I'm not premature with this verdict, but I just got rid of the very light, very small, compact Westell modem ATT gave me. ATT sent me a slightly heavier Motorola modem. I've been using the Motorola for about half a day now. It's about the same size as the Westell, compact in size. Does size matter modem-wise?
The same vids that failed with the Westell now run stream fine with the Motorola. I ran about 8 vids both with IE and FF all at the same time and they ran fine with no drop-offs. Also, in the last couple of days, besides the streaming problem, on occasion out of the blue I'd get the IE Cannot Display the Page error message. My browser would stay stuck on that page for a couple of minutes no matter how many times I'd hit Refresh. This would happen on a rare occasion.
I was with Time Warner for about 6 years. Their heavy, large Surfboard modem never failed - I'd rate it A+. I've been with ATT for about 2 months. I thought TW's customer service was bad - and at times it is. ATT has some serious customer service issues that need fixin' and appear to be worse than Time Warner. I hate'em both they both SUCK but whatta ya gonna do you need an Internet connection.
My mom's dead but even so I still wonder how anyone with a heart purer than mine could ever deal with someone like them. Seeing what we, the consumer, have to deal with nowadays, it's just as well that all the pure hearts of yesteryear have been replaced with girls gone wild. Which suits the the suits at ATT and Time Warner just fine. Why, they figure, rise up to cater to the needs to a class of people they find dispensable? In their eyes we're all gang bangers, not veterans of war.
Change is needed. My one grand wish is that Rupert Murdoch and the head of ATT contract H1N1 this coming winter. I tell everyone that Wikipedia's database is bigger than the galaxy - don't doubt me on that 'cause they even have a page on pubic hair. I think mom woulda got a kick out of Wikipedia.http://en.wikipedia.org/wiki/Influenza_A_virus_subtype_H1N1