Monitor power down problem

Prior to this problem showing itself, I sorted out issues which started with

micobill.sys infecting my machine.

Having completed that work, I notice quite a few changes on my machine most

of which, so far, I have been able to get back to normal but one is causing

difficulty.

I set the monitor to turn off after 15 minutes using control panel>power

options (15 mins) >apply>OK but nothing happens.

I have rebooted/tried different times etc. Sometimes when I finally hit 'ok'

I notice that random times pop up in 'sytem standby' and 'system hibernates'

boxes just before that screen disappears - but not always.

Ideally, I want to set 15 minutes for monitor power down and 2 hours for

system standby but have been trying to achieve one setting at a time because

of the problems I am having.

Thanks for any help you can offer.

Ray