As for your current connection problems, try some basic troubleshooting steps...
First, try to connect your computer straight to the modem, bypassing router.
If that simple step doesn't help...
Turn off computer. Disconnect router, and modem from power source for 30 seconds.
Power them back on.
Restart computer.
If that doesn't work, bypass router, and connect computer straight to the modem.
If that doesn't work...
Go Start>Run (Start search in Vista), type in:
cmd
Click OK.
In Command Prompt window, type in following commands, and hit Enter after each one:
ipconfig /flushdns
ipconfig /registerdns
ipconfig /release
ipconfig /renew
Restart computer.
If that doesn't work...
Go Start>Run (Start search in Vista), type in:
cmd
Click OK.
At Command Prompt, type in:
netsh int ip reset reset.log
Hit Enter.
Type in:
netsh winsock reset catalog
Hit Enter.
Restart computer.
If that doesn't work...
Download, install, and run WinSockFix: http://www.softpedia...inSockFix.shtml
Restart computer, and check again.