keep getting dumped, theres a few different things?...

ok well i get dumped of the net, and run the diagnostics, it says its my modem right.....well half the time its not as i have my other computer pluged into the modem too and it runs online when this one craps out, usialy i have to start the modem twice for it to sort it, then.... not to often it goes to a blue screen and says something about mem dumps? it could go weeks without doing it then do it 5-6 times in one day out of the blue. i asked my toutor at corse and she said it could have something to do with my browser and that 1E needs updateing to 7 or something?, but i dont think so, any of you good fellas got an idea, i dont think its to major but its a pain in the arse when you have a realy good poker hand AND THE COMP DUMPS YA! (like i said half the time the modems running fine) im stumped! cheers in advance

ok the shit comp is running vista
my other is just xp i think. < not that it mattersmajor