Windows XP - very slow networking

I have recently moved 3 computers to a new office, where I am jumping onto a simple network. The 3 computers were previously on a home network with a static IP configuration - LinkSys routers - worked fine and was fast.

At the new location, 2 of my machines are working fine. The environment is now DHCP. One of the machines is VERY slow to access the network resources or any web pages. The local resources are fine and I can browse the local disks fine. But any network resource takes forever to load or doesn't come up at all.

Last night I installed a freeware program called Cablenut to diagnose the bottleneck and got speed right away. I thought the problem was solved. But today it is back and Cablenut isn't helping.

Does anyone have a suggestion of where to look to diagnose this problem?

I have flushed all the old Static IP settings out of the system, and all the machines are configured the same way, but I am pulling my hair out. Any ideas greatly appreciated.

Is this a workgroup or a domain? Have you checked the event log for the computer in question?

Yes this is better to look at the event views and see which applicaiton has error and which applicaiton is not working properly

Thanks for your replies. I have looked extensively at the event logs and found nothing that seems to be causing it.

I can shed some further light on the problem as I have learned what events seem to be causing it. I had multiple external drives connected to this computer before I moved it to the new office: A ZIP drive (parallel), A card reader (which is read by windows as 2 drives), and a DVD burner (via firewire). Since I moved the computer, the only way to make the super slow down of my network connections stop from occuring is to remove all those drives from the computer, and then run the TCPOptimizer from Speedguide.net to "Restore Windows Defaults" to my TCP/IP setup. Then I have to reboot and all is up to speed.

But if I then try to install the ZIP drive or any of the other drives, the system bogs down again.

Any further ideas out there? I am really at a loss.