OS 10.4 - problem when putting laptop to sleep...

setup: 1 month old macbook pro working with tiger...

this started to happen after i've checked the box to deactive the automatic login so it asks for a password... (before, when closing the laptop it went to sleep, not waking up until I reopened it)

when i close the machine now it goes to sleep and turns on twice before going to sleep definitely (apple light in the back turns on), then goes to sleep but wakes up twice from time to time (all this remaining closed!) before going to sleep again.

and worse, when opening the laptop it doesn't automatically wakes up as before, but doesn't wake up at all even when touching some keys... only with a power off button press...

have now unchecked the (automatic login) box again but it keeps asking for password when booting and doesn't wake up when coming back from sleep...

also computer does this when being on power OR battery...

any suggestions?

many thanks
claus