Hi
you can go for missing event id monitor in scom refer below link for more information.
http://technet.microsoft.com/en-us/library/ff629447.aspx
(or )
you can go for powershell script base monitor to check for given event id in respective log and generate alert if event id not logged in last 25 hr.
refer below link how to create an power shell script base monitor
http://technet.microsoft.com/en-us/video/jj133829.aspx
powershell script
<![CDATA[
$api = new-object -comObject 'MOM.ScriptAPI'
$bag = $api.CreatePropertyBag()
$e=Get-EventLog -LogName system -EntryType error -InstanceId 5722 -After (Get-Date).addhours(-25)
if($e.Count -gt 0)
{
$bag.AddValue('Result','Good')
}
else
{
$bag.AddValue('Result','Bad')
}
$bag
]]>
regards
sridhar v