LaCie External HD not mounting on new MacBook Pro

Hey..
I'm at work and my LaCie 750MB hard drive will not mount on my week-old MacBook Pro (OS 10.5.2)....

I've connected it to other Macs in the office and it will mount. I've also switched out the cords, so that's not it. The HD also mounted on my laptop earlier today. I've been playing around with the System Prefs... but everything looks right. Also, Disk Utility is not recognizing the HD.

Pointers?

How are you connecting, via USB or Firewire?
Also, in Finder's preferences (General Tab), do you have "External discs" checked off?

Thanks for the reply....
In my finder Prefs I have external disks checked....

It seems that by restarting my computer seems to have fixed the problem... hum..

That will do it. Sometimes, it's those simple things.......