Just follow the directions. (You may need the original disk for repairs.) Anyway, as to what I can remember, if you ARE having trouble deleting files, you would need to restart, then when you see your entire desktop, hold down the shift key (I think) when emptying the Trash.
Running 10.6.4 on a 27" iMac 3.06 GHz C2D.
I was irritated by sometimes not being able to empty items from my trash(message that file was in use when it wasn't). I found on lancelhoff.com a command for terminal(cd ~/.Trash && sudo rm -rf ) followed by directory/filename which allowed these pesky files to be deleted which worked great. I was showing my manager the trick I'd found and while doing so, it stopped deleting the files. Now when I put items in the trash I get a message 'Are you sure you want to delete "xxxx.yyy"? This item will be deleted immediately. You can't undo this action" instead of putting it in the trash.
The files I was trying to delete when I was doing my doomed demo will not delete even after a restart.
I did a fix permissions on my drive with Disk Utility which was no help in this regard.
Can someone tell me how to get my trash to function normally again.