My macbook 13" 10.5.8 leopard, won't wake from sleep

When I close my computer it won't wake again without restarting. Then I see a gray screen, eventually turning to blue and eventually I can use it. This has happened 2x before and somehow months later started working again. It happened again and I can't figure out what to do. I've reset the pram and no difference. I don't have anything connected to the computer and the "energy preference " is ( I don't think) the issue. HELP ???

Boot with your original install recovery DVD and use Disk Utility from the DVD to run verify and repair on the hard drive. Let's see what it says.

Hi and Thanks for responding. I didn't use the DVD but I did run Disk utility to repair permissions. Is that the same thing, or is what you're saying totally different?

In order to test the hard drive you must boot from the install DVD that came with your machine. You run Disk Utility from the DVD to do a verify and repair on the hard drive. You can't test the hard drive while it's mounted.

Repairing permissions can be done either way but I didn't ask you to do that.

Okee dokee.. thanks for the clarification.. I'll try that and let you know what happens.

I used the install disk as you suggested and It said " no trouble found" so I went for the extended testing and it too said " no trouble found". Any other suggestions would be greatly appreciated. Thanks again!

OK. Let's try resetting the SMC. See the following Apple KB article for the procedure: LINK

I actually tried that before anything and also restarting holding down the command, option P&R too.. Did not help the first time and did not help this time! So frustrating.. Any other suggestions, or is it time to take it in?