Mac OS X Lion boots very slowly takes 2 minutes to start
Try a...
PRAM Reset

Shut down the computer.
Press and hold the ⌘+⌥+P+R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.

Why could this help? -&gt;
Information stored in PRAM includes the startup volume choice.