how do i fill my chaffeteaux et maury sterling pp combi boiler?

My boiler is showing no pressure on the guage and if i try to bleed the rads up stairs there is no water or air coming out. Also if i try to switch the boiler on the fan runs to purge the system and the pump runs, but there is no heat or hot water. The main burner will not light, I believe this is due to the lack of water pressure in the system but there is very good water pressure to the house. We have recently moved into this house which was empty for some time. Before the system stopped working all together it would make a whining noise for about 5 mins after start up and when called to provide hot water.
thanks