Could also be that your AV is scanning all the packets going threw it. Or maybe your firewall is running an IDS of some sort or maybe its routing the packets wrong. If you have a 4 port router infrunt of your computer whats the point of running a firewall? seems like over kill if your worryd about safty. Try turning those off to see if helps. If you need help post again, dont just try firefox because you might just be running from a bigger problem. Try to fix it first.