OK, seems to be MC related. I found from evet log (Media Center part):
"Seuraava ohjaimen ajastettu lataaminen tapahtuu 4/9/2008 4:0:0." meanin
time for next scheduled driver download time.
I also looked Jon's proposal for optimazion, it was uncheked. I cheked and
added time 19:00.

Additionally I tuned "mcupdate" from scheduled tasks, let's see if these
magics works.
Thanks for your quick advices!

"Markku T." wrote:
[color=blue]
> I record TV programs with WMCenter using scheduled recording. This works fine
> also if I put PC in sleep mode, it wakes up and record. Vista goes back to
> sleep after recording but wakes up to do something at 4:am. Earlier this
> didn't happend, so there must be some new timed task. I can not find what it
> is fom "scheduled tasks". Can anyone advice me?[/color]