If logon is fast "network cable is unplugged"

I've been experiencing that problem since upgraded to XP Pro SP2. If
my logon and XP loading process is fast and if i logon via AUTO-LOGON
and although my ethernet cable is plugged properly, i get "network
cable is unplugged". This is such a fake because i can browse websites
normally although that message.

A tip worked me for a long time but still suddenly i got the same
problem:


Start > Run: GPEDIT.MSC > Computer Configuration > Administrative
Tools > System > Logon > Wait for the network at logon and restart >
activate.


But strangely started to get the same problem and my windows loading
time became very shorter than before.

How can i fix?

Thanks.

Isn't there any experience about this?

Thanks.