problems with spinning beach ball and applications randomly quitting themselves

for the last month or so my macbook keeps on giving me the spinning beach ball, even when i am trying to do a simple thing. when i try to watch a dvd it happens and i can even pause it or escape and it often quits applications and sending error reports
i have no idea what to do... please help

I had that problem, my HDD was dieing, those could be unrelated though.

G'day and welcome to the forums.

Boot from the original discs that came with the machine, hold down 'D' to enter Apple Hardware Test and run extended tests. Reboot from the install disc if all is well, go into Disk utility and run Repair Disk and advise what is reported.

You do have the original discs? They are essdential troubleshooting tools.