Hi there
I can give you a few things to check.
Open IE and goto the "Tools" menu and select "Internet Options".
Goto the "Connections" tab and select the "LAN Settings"
If your office is not using a proxy server then uncheck all except "Automatically Dectect Settings" and apply.
You could always select the "Never Dial a Connection" while you are in the Connections Tab if you don't won't the dial up connection box poping up.
Next, what security are you using on the access point (AP), if it is anything higher than WEP you may need to update the drivers of your Vaio laptop as there can be compatibility problems with older drivers, as the standards have changed alot in the past two years.
Thats all for now.
Good luck
Dale