Speeding up boot process by managing Wifi devices ?

[Linuxguy123]

I seem to be rebooting my laptop a lot lately.  Unfortunately, its a
slow process.  

I watched the textual output during a reboot and was surprised to learn
that most of the time booting is spent on two Wifi related events:

a) Determining IP Information for wlan0

b) Searching for the nntp server, even though wlan0 did not connect to a
network.

I am running KDE and I've got Network Manager enabled, so once I log in,
its asking me which network I want to connect to and then connecting to
it.

All in all, I must be waiting several minutes for my wifi device every
time I reboot.

Is there a way to change this behavior so that:

a) my computer isn't trying to connect to a network when rebooting ?
b) its not trying to connect to the time server when it doesn't have a
network connection ?

Thanks