MacBook not shutting down properly after Leopard installation.

ok, this is a funky one. i just did an archive and install with Leopard, from tiger. after installation, i downloaded a few apps, that were updated for Leopard, and all was well. i tap the power button, revealing the menu that asks if i want to shut down, sleep, restart, etc.. i click "shut down". computer shuts down.

when i go to close the MacBook up, the indicator light on the front comes on. i then open the lid and it shuts off. i do this again and again- same thing.

so i go to start my computer. i push the power button- nothing happens. i hold it down for 5 seconds then push it again- computer boots up. after login, i get a message saying that the computer unexpectedly shut down.

if i shut down again, this process repeats. however, if i start the computer in the same manner as i described earlier, but do not log in and shut down directly from the login screen, computer shuts down properly.

the condition i described earlier sounds like the computer is not fully shutting down. while the screen goes black and everything stops running, it's acting like it has not fully shut down- almost acting like it's in sleep mode, or sleep/shut down mode. since i have to hold down the power button for 5 seconds, then push it again, it seems as if i am forcing the computer to power down, then restart, thus giving me a message saying the computer unexpectedly quit after i log in (i hope that made sense).

this has only started since the Leopard installation.

anyone else have this problem? i don't know if it's something i did, Leopard did, or what. any help would be awesome.

otherwise, i really like Leopard for the most part.

Thanks!