Variety of help/problems with a Macbook...

Ok, so a couple problems I'm having with a black Macbook, few months old, running Leopard, with an external monitor.

1. Have a folder in the trash that will not empty. The "Emptying Trash" screen can't be cancelled, I've tried secure empty, and also some program called Trash It, as well as a restart, and no luck. How do I get rid of this?

2. Since yesterday, when I reboot, at a white screen I get a quick "snippet" of the startup sound, which then gets cut-off, and continues to repeat this cut-off sound over and over, until I press the power button to shutdown and then turn it on again, at which point it boots properly.

3. Movies at 1080 resolution have choppy framerates...I've read that the Macbook should be able to handle playing this size video...

4. Using the new USB Apple keyboard, sporadically, and now for the last several days, using Apple + Delete will not delete files.

So, any help is majorly appreciated...maybe a Leopard reinstall will help a bit?
Thanks!

Item one is a problem and is being discussed here.

Ok, well, number 4 is still a problem, can't figure it out.

And, I think this may be a different problem, referring to 1. I've now formatted and reinstalled, and stillthis folder is in the Trash...