I couldn't find a topic for this particular problem. The Skype 3.0 logon process is taking over 2 minutes. It is also using up 100% cpu during the process. Every time I hit the close button, where it would normally minimise skype, it's crashing.

Suspect fire walls if this is upgrade. See below:

With updating SKYPE your firewall must be updated as well.
Exit/Close your current Skype by clicking in system try Skype icon (down near the right corner green spot)
and choosing “Quit” from there if needed.
Open firewall, in programs, deletes Skype.
Run Skype and allow connecting
This also affects SP2 users who should follow above procedure.
With SP2 firewall.
Disabling external firewall will enable XP firewall by default.
So if you disable any other firewall XP firewall will now block your connections.
So remove Skype from XP firewall program list as well

see this as well
http://www.skype.com/help/guides/firewall.html

Norton Firewall
http://www.skype.com/help/guides/firewall_norton.html

Also read this:
http://service1.symantec.com/SUPPORT/nav.n...svy=&csm=no

SP2 Firewall
http://www.skype.com/help/guides/firewall_winxpsp2.html

Zone Alarm (pro)
http://www.skype.com/help/guides/firewall_zone.html