Ok everyone just take a deep breath ....... there now let's review:
BMan: Mainframeguy posted a utility that allows you to change the MTU on a selected Network Card. After you run the program and agree to the terms you are presented with a list of your network devices. Locate your network card that is connected to your router and click edit, now enter the desired MTU value. If you have wifi as well may as well do it for the other one. Click Ok then next and reboot when it recommends it.
Now if you went through this then it is quite possibly that the problem lies somewhere else. As I have mentioed on MSN, while trying to track down a MSN problem of mine I decided to test an old Linksys router I had lying around and this router wasn't up to par. I noticed quite a speed drop and such which I think it linked to it's age.
Now what you could do, is purchase a router, try it out for a few days and if the problem persists then simply return it for a refund.
Mainframeguy: From your posts it sounds as if you are getting fustrated and I can sort of see why as I am having an issue on another forum where Im asking something but instead I'm getting the work around. Bman has mentioned to me via MSN, he is new to networking so we need to be patient and more undersanding.
Now from what I gather, turning the firewall off in the router seems to help fix the problem. Since this may be the case it could indicate that the firewall in the router is either malfunctioning or not up to speed. With my linux router box I had the issue of when using a Intrustion Detection service it will block some site's IP for reasons unknown, once I unblock it the site loads.
So there can be two options here:
1. Buy a new router and test it out to determine if it is indeed the router or
2. Just disable the router's firewall and install a software based firewall like Zone Alarm on EACH computer on the network since they all may be open.