Udp flood attack

Hello, I’ve been having this problem lately with some guy wanting my nick on irc so apparently he does these udp flood attacks against my computer. These show in comodo logs as udp port scans and udp flood attacks with A LOT of packets going to just random udp ports (last time from four different sources) and the firewall switches to emergency mode. I have the default network rules with nothing allowed in and don’t have any programs to listening to any ports. The problem is that during the attacks, which last for about five minutes, my computer used to hang totally. Now that I have a quad core processor it seems to hang only one core and I can use my computer normally but during the attack my all excisting connections seem to drop out and I can’t make any new ones and this results of course me timing out from the irc server. From the local area connection status I can just see a lot of received errors. I’m using the comodo firewall with windows xp. I have a 100Mbit/10Mbit internet connection. So is there something I can do to prevent these attacks?

If the flood attacks are from the same i.p than create a block rule.

They are mostly from different ip:s but they should already be blocked by the last default network rule and atleast seem to according to the logs but still causing the problems I descriped in my post.