MacBook Pro running terribly...

It is slow, trackpad/cursor skips all over the screen, it is freezing randomly... it is not a memory issue, as i have just moved a substantial amount of files off of the HD and even before i did so had plenty of memory to spare...

Will not shut down manually, have to do a hard reset to be able to power off the machine.

Have tried repairing permissions, has not seemed to help...

Any help here? I think it may need a thourough cleaning, I consider myself good with computers but by NO means an expert lol... so if anyone has any ideas as to how i can find the problem myself it'd be much appreciated!

Thanks

Since you neglected to give us any info about your Mac or which version of OS X it's running - try doing this:

Boot the machine with your original install DVD and enter Disk Utility from the DVD. (top menu, Utilities, Disk Utility) Run a verify and repair on the hard drive. Let's see what it says.