A colleague on a Windows 98 machine had trouble logging into Admango.com (a subscription-based monitoring service for Hong Kong advertising media). She'd enter her username and password but after clicking the (Javascript) Submit button nothing would happen. A few times Internet Explorer's status (bottom left corner of window) would show the form data being submitted to "do_login.asp" but it would get stuck at that. She had no trouble accessing other sites or any local network resources such as servers or printers. She could also use her username and password on other PCs without a problem.

Initially, I figured Javascript might have been disabled (or somehow messed up) so I reset Internet Explorer's Security settings to their default values (Medium level) and examined the values. I also deleted all browser cookies and temporary Internet files. This did not resolve the issue so I upgraded Internet Explorer from 5.5 SP1 to 6.0 SP1. Problem was still there. Another strange circumstance was that she was able to log in instantly using Admango's version 1.0 Login screen. With Admango's version 2.5 beta Login she'd get an "Invalid Login Name, Password, And/Or Insufficient Priveleges" error. This was consistent: 1.0 Login = success, 2.0 Login = no response, 2.5 beta Login = error.

At that point I began to suspect that her network interface card (NIC) might be the culprit. I found out that her NIC was an old Compaq 10Mbps ISA-type NIC. I swapped in a 3Com 10/100Mbps PCI NIC and that did the trick!

So the next time you experience any strange network problems, don't rule out a bad NIC as being the culprit. Other hardware such as memory and even the power supply can cause what would seem to be software issues as well. Accordingly, if you're building your own PC, don't skimp on the motherboard (MSI is good), power supply (SPI is good even though their site sucks), memory, and NIC (3Com is good). But then again, these days, why build your own when you can just buy a DELL with a nice 3-year warranty?