Windows

Do you do the continuous ping from when the machine is first available? Or do you start the ping after the machine has been on for, say, half an hour?

I am wondering if it is taking a while for your firewall to kick in. How long before the computer is available after log-on? Do you have to wait a while before spps start responding??

Does your PC scan the network to see what is available each time you log-on?

Check your event logs and see if there are any errors.

There are many things which could be causing this.

your input clues aren't that much but it looks like that your NIC is busy searching the net to see where it stands . If you are on a lan :
1. change the utp port on your switch .
2. see if your ip address , comp name , domain name , gateway add are all ok on the pc .
3. change the pc with a working pc to check your patch cable, switch port etc.

You have provided a very sparse problem description that can be caused by any number of things.
Microsoft has apparently decided that desktop functionality is to be given the highest priority during the boot/logon sequence. If you wait five minutes after booting up and then retest does the netlogon happen fast or slow?
If the problem does not occur at this time, try to minimize the number of services that are started at boot time to those which are actually required.

In your network are you running a lot of GP's? If you are running a lot of GP's in an Active
Directory environment you might have to rething your GP structure if everyone is having a problem on all your machines. If it is only on the one machine, I would check the network architecture from this machine to make it simpler.

Is there a logon script that you use that disconnects and reconnects mapped drives?
Reduce the length of the logon script or remove it and then retest.

Are you running DHCP? Maybe you have a bottleneck with your DHCP server being hit too often.