A DDoS will only slow down your network, not your computer (unless you're using a virtual modem or something archaic like that).
Distributed Denial of Service (attack)
I guess it stands for both Direct Denial of Service and Distributed Denial of Service.
I'll be honest, this may sound weird, but I'm not really familiar with what a DDOS does. All I know is that it slows down computers and, if enough packets are sent, it renders the computer useless.