I have this problem with a couple computers at work. Here is the issue:
Computer will not display network icon in the system tray. When trying to access anything internet related, nothing works. IE Page not found errors, etc. When I go to Control Panel > Network Connections, my computer will hang and I have to close control panel from task manager to continue. My computer will also freeze/hang when I try to use some other applications that require an internet connection.
Restarting usually doesn't help. The only way I've been able to fix it is by turning it off for some time, and turning it back on later. But even this doesn't work 50% of the time. Restarting over and over again does nothing; the computer still acts the same, no network icon / freezing when accessing network resources. Once it does decide to work however, the computer has internet/network connectivity, and no problems until it is shut off again.
I've tried all the drivers out there for my network adapter, and reformatted 3 times so it's not a virus/spyware. The current computer I'm having an issue with is a day old with no applications other than Windows Update, Microsoft Office, Java, Flash, and Adobe reader installed. They are all Dell computers, some are Vostro desktops, while some are older Inspiron's. All computers with issues are running Windows XP SP3.
I can try that but it's so intermittent that it would be hard to determine if that works or not. Most of the time, this issue only happens in the morning. Whether that is a time-based thing, or has something to do with the machine being off for a period of time, I do not know. But for instance, right now, it is 10:00 am and the computers have been on for an hour now. Even If I continually restart, I won't encounter the problem.