is that on the face of it this isn't a hardware problem at all - it seems to point to an error in the operating system.
Under the terms of the Microsoft OEM licence your retailer is responsible to you for any problems with Windows, so that's the first thing to remember. In addition, Comet is liable to repair any faults that manifest themselves within six months of the date of purchase - the law assumes that the faults were present at the time of purchase. All you needed to do was dump the problem in Comets' lap, and let them sort it out, but you didn't know that, and as a consequence you have reached this impasse with Toshiba.
The company may well be right when it says there's no fault with the machine - I imagine they'll be talking about hardware, not software. They are the makers, and if they say the machine has no faults it's a pretty good bet that they're right. The fact that you have been unable to access either the Adobe or the Norton update sites explains why Toshiba has suggested a router problem. In fact it may be an operating system problem, as I said at the beginning.
Either way you're in a difficult poisition now. Toshiba's warranty only extends to the machine's hardware - the company is under no obligation to remedy software faults. Comet was under such an obligation, but they might take the line that you have lost your right to their help by going to Toshiba.
I don't take that view, however, I still believe that you can require them to rectify this problem under the six month provision, and I suggest that you tell them so.