Net speed dropped after a few days. Why?

[ikari120378]

I am using Compaq Presario v2000 notebook connected to my office's LAN. The softwares are WinXP SP2, and Norton Internet Security 2005. The first day I connected it to the network the internet speed was so fast, opening websites were just in a blink of an eye. But no network computers were shown at all, that I suspected norton blocked it automatically. In the first days also there were several notifications from norton to create rules for some programs. 3 or 4 days after up until now, the net gets so slow, and sometimes can't open a single website in a single shot that I sometimes have to refresh it a few times. Recently I tried disabling the norton (but not the antivirus), the network comps are all listed, and the net speed improved, but only a little. What could possibly be the cause of it? Could it be the norton? Anyway, there are several LAN workgroup (mshome, etc.), would changing it causing a significant effect (maybe a different workgroup shares different speed)?
Thx a lot!

[Force Flow]

First things first, uninstall Norton. The whole package.

Install AVG for AV software and make sure the SP2 firewall is enabled. Or, if you want to disable it, take a look at sygate or kerio.

[sgtspector]

Also check to see if there are any win 98 or older pc's on the network, When being browsed they slow the whole process substantially. Check MS knowledgebase for details and a fix. Dont remember the particulars but it is a known issue.