Dock, expose, start up and volume keys issues

(This is all occuring on an intel imac 1.73 core duo, 1gb ram, OS 10.4.11)

Where to start, about 3 days ago my mac took ages to boot, it just sat on a plain white screen before eventually loading the white page with the apple. Sometimes I have to restart at that point because it doesn't get anywhere. It still happens at least once a day.

I have my dock hidden and it's not responding when I go to the bottom of the screen, it appears if I click but then when I go to hover over a different application the magnification doesnt follow it.

My volume keys on my keyboard and remote havent been working.

Expose hasnt been working either.

And finally when I hover over an icon the pointer doesnt change and it doesnt highlight the icon I'm over. This is also occuring with the toolbar at the top of the screen.

I havent installed anything since last monday and that was only BFD2. On some restarts it's ok, it's doing ok this time but I have unplugged most of my USB's and firewire. These items include 2 external harddrives, my phone charger, my ipod cable and my logic key.

Any ideas would be truely helpful cos I'm at a loss for ideas. Thanks.

I've unplugged everything except my mouse and I have a bluetooth keyboard. I've tried repairing the harddrive and the permissions

Everything checked out fine, the only thing I've done around the time of it starting was I got a harddrive caddy for my old harddrive. But I've plugged that back in and it seems to work fine. I wouldnt worry too much, my new mac has just been shipped today and I'll do a fresh install on this one when I sell it.

But thanks for responding it might have just been one of those things.