Measurement under load (entry capacitor) - is "this" normal ?

Hi,
yesterday when i left one LCD monitor was OK.
Today i was gonna make final look and assembly it.
I was working calm and think everything should be normal.
There was no Image and now even without Display the power LED doesn`t light.
The questions :
Is it normal when measure entry big capacitor (150/450 in this case) the multimeter to show variable values - 24 then 03 then O.L ?!
What can be that from - which element on the board or ?
When i measure voltages in the end of the power board which are going to display board what type of voltage should i measure - ac or dc?
at all if i measure on mode ac(dc) but the voltage is dc(ac) what is gonna to happen - will the multimeter fail?

thanks