• Ping of death is an another type of DOS attack that can shut down systems, and causing a great harm to the system.
• Default ICMP echo packet size of 64 bytes, many computer system could not handle the incoming packet larger the default packet size.
• In ping of death attack an attacker generates ICMP echo packets of over 65,535 bytes that is illegal.
• If you ping to a host like ping 192.168.1.1   
• What would happen if you do this thing like ping 192.168.0.1 -l 65500 -n 10000
• This, in effect, pings the target machine 192.168.0.1 continuously [10,000 times] with 64 kBs of data.

• Distributed denial of service attack or DDOS attack is a attack in which an attacker uses several machine to launch DOS attack that’s why it is difficult to handle.
• In DDOS attack multiple compromised system that already infected are uses against the victim computer.
• In this case it is difficult to track the attacker because this attack generates from several IP addresses, and it is difficult to block.

There are no any single way to prevent DOS attack because of it varying nature, there are some effective way to avoid and reduce to effect of this attack.

• Install and maintain anti-virus software.
• Install a firewall, and configure it to restrict traffic coming into and leaving your computer (Firewall ,Firewall 2)
• Here is a nice article on Defense against SYN attack.