That switch occurs when there is packet loss on the network. The location of the loss can be all over the place.
Some things locally (on your PC) that will cause this:
1) Anti-virus programs running in background
2) Instant Messengers running in background
3) The Microsoft Auto-Updater
4) Any email software running
5) A misconfigured firewall.
6) A personal router
7) A USB connected DSL or Cable modem
8) A winmodem (software based modem) on a dial-up connection
10) Interrupts being shared in your computer.
Non-local culprits:
1) An overloaded router at your ISP, or anywhere on the Internet
2) A cable connection whose node is overloaded
3) Excessive errors on the Internt connection (tough one,..could be software or hardware)
For the most part, the above should cover 90% of the potential causes of packet loss.
