Server coming on by itself

Hello, testing out SLES 10 SP2 on an old Dell PowerEdge server. At 8pm
every night this server just powers on by itself. After going through BIOS
settings I couldn't find a cause on the hardware itself.

Then I tried in SLES to disable NTP, set the SLES clock to 19:55, powered
down the machine, waited about 5 minutes, and BINGO! The machine started up
at 20:00 based on the SLES clock (even though the BIOS clock was well past
that).

I can't swear to this, but I think this started happening about a week ago
when I wiped the system completely (all partitions) and re-installed SLES as
I hadn't allocated partition space properly.

In any case, does anybody know where I should check for whatever conceivable
setting may be causing this server to power on by itself at 8pm?

Thanks in advance
James