Vista DHCP Static Switch causes problem

Hi,
I use DHCP at home and need to use static IP address at work. I have
static IP address & info filled on alternative tab in IPv4 on LAN
connection. I disabled IPv6.

I have no problems with DHCP so far. But, with static - I get
connected to the internet and sometimes - I don't.

a) If it cannot get assigned to IP properly - computer does not
shutdown properly. I just have a screen that says 'Shutting down' for
long time. I have to use the power button :-(

b) Once I am connected, if network cable gets unplugged and after
plugging it back in - I can't get connected.

c) WIRELESS: This one has to do it wireless. After using a wireless
connection, shutdown does not work properly. Again, I just have a
screen that says 'Shutting down' for long time.

Any help is appreciated. Thanks.