I'm working on a HP Pavilion 4535, 400mhz, 256mb RAM. This is a dual boot (win2k and win98) Windows 2000 had service pack 3 installed. Customer runs a VPN over the internet for a travel agency business she operates from home. One morning she was running ok but seemed slow so rebooted and the problem started. The modem connected to the ISP but the internet would work only once in a while. ie: 4 out of 5 times the internet wouldn't work.
Norton was updated to current definitions and a scan was done, but nothing showed up. She had run Ad-Aware every day, but the last 3 times all it removed was cookies. I saw this problem once before when spyware was removed. Modem would connect but you couldn't go anywhere. Restored spyware and it was ok. So just to be safe I restored the last 3 quaranteened items. Nothing. Installed service pack 4, hoping it would fix it. Nothing. Now the internet doesn't work 100% of the time.
If you boot to win98 everything works 100% of the time, so the modem is fine.