Here are some possibilities:
1. Make sure you flash your router with the latest firmware Viewsonic has available for it.
2. Change your router's wireless channel.
3. Check how long your router's lease time is set for.
4. Call you ISP and ask them how they manage IP lease times on their end, plus tell them what the problem is and see if they have a solution. Perhaps you need to have your e-mail client check for e-mail every 5 minutes, or use a program designed to keep your connection alive if you have that instead. Anything to show your ISP you are active. Or purchase a static IP from them.
5. It could also be your adapter causing the problem, so check for updated firmware there too (Netgear adapters, for instance, were often the culprits rather than their routers when all kinds of connectivity issues arose for them following the release of XP-SP2).
6. Call Viewsonic and ask them for help
--David
p.s. - do you have any computers that are wired to the router? If so, do they also get disconnected, or is it just the wireless ones that do? Lastly, when you find that you have suddenly lost connectivity, if you bypass your router all together and re-plug your Internet connection directly into one of your computers, are you still off-line?
