application launching failures

[Bart Silverstrim]

Hello,

Here's an odd problem that seems to have started up in the past week  
or so.

I have a MacBook, black, running 10.4.8 on an intel 2GHz core duo, 1  
gig 667MHz DDR2 SDRAM, this is the spec as it came from Apple, no  
upgrades or alterations to the hardware since it came in.

I'll have a series of applications open.  At the moment, that would  
be Mail, some Finder windows, Adium, Overflow, SSH Tunnel Manager,  
and SMARTReporter.  I also had iTunes running at the time, but shut  
it down when the behavior appears.  Connected to the laptop: a USB  
mouse and firewire iPod, network cable, power cable, headphones.

Then I will go to start, in this case, iTerm.  It started up but  
wouldn't bring up a bash prompt, as if new processes cannot be  
spawned.  Apple-T brings up a new tab, but it's labeled "shell", and  
never finishes bringing up the shell prompt.

If I clicked on FireFox, it bounces for a long time in the Dock, then  
just sits there without the black arrowtip under it.  Again, as if OS  
X cannot spawn new processes.

This happened yesterday when I had a second monitor hooked up.  I  
disconnected it, doesn't help.  I ran the disk utility from the  
installer disc and had it verify and repair permissions, then verify  
the hard disk.  I had it repair permissions, but the disk verified  
fine.  SMARTReporter still says there is nothing wrong according to  
the drive.

Logs, I can't check at the moment, because it's unable to launch  
anything that will let me view the logs.  It's suffering from this  
problem *now*, as I am typing this.

Has anyone seen or heard of this type of behavior?  Nothing new will  
launch, and I will have to restart it in order to get functionality  
back (although I'm first going to try logging out; as I recall, it  
wouldn't shut down last time I told it to shut down, and will have to  
hard-shutdown the MacBook anyway.)

Help?  Tips?  Advice?