T42 suspend problem

[mlli4]

I try to configure my T42(23746vu) to suspend to ram automatically ater 30 min. But it never suspends when AC power is pluged.
My setting is (AC power is on)
hibernation disabled
shutdown LCD after 15 mins
shutdown HD after 25 mins
standby 30 mins.

However, if I set standby after 25 mins, then suspend works.
Anyone has the same problem?

[GomJabbar]

My guess is that you have some service or automated task running. Go to Start > Control Panel > Administrative Tools > Event Viewer, and see what was going on when you were trying to enter standby unsuccessfully..