Lower your MTU
If you are on XP, download

and change the MTU to 386.
If on vista/w7, open cmd.exe/command prompt and paste this line in.
Code:
netsh interface ipv4 set subinterface "Wireless Network Connection" mtu=386 store=persistent
For wired connection
Code:
netsh interface ipv4 set subinterface "Local Area Connection" mtu=386 store=persistent