Linda,
I have a suggestion, but i am not sure if it can help you and it may mess up your system. Do not attemp this if you are not technically comfortable (or without a backup or a restore point of your system). I think it is a little bit risky without a backup.
I don't know if you are running windows XP, but if yes, disable the windows firewall for a while after disconnecting from internet.
Install zone alarm (firewall free for personnal usage).
http://www.download.com/ZoneAlarm-Firewall-Windows-2000-XP-/3000-10435_4-10039884.html
Normally, in the old time when i used this product (i don't know for recent version), there was a kind of learning mode (you can use this mode). Each time a software will try to access the internet, a popup windows will happen from zone alarm that will ask you if you want to allow the program to go out on the internet (you may answer no to see what will happen, take care to not accept this forever because it won't show any popup later). This way, you will see if it is related when S&T is trying to access internet when it is dying. I don't know if it is possible to achieve a similar behavior with win xp internal firewall, because i seldom use it.
It is not a solution, but only a mean to get additionnal information on the problem. You can revert back to the system restore point (or backup) once you know enough about this.