Worcester 240 combi - all lights on but no heating no hot water?

Hi, I have just moved in to a house and the boiler worked fine (well, it was heating the rooms but hot water was very intermittent) for a few days and now it is not heating at all. No hot water either, before it was intermittent. Both lights on the front panel are on. One is red which I guess is the power supply light and one is green which says "demand". Earlier it used to make bigger noise but now it is a very low humming sound. The pressure when not in demand used to be about 1 bar (the red needle is set at 1.7) and when in demand it used to rise to 1.5. Now it sits at 0.7 and stays like that when in demand or not. I have downloaded the manual from the website but can't figure out much. I'm a girl so friends suggested that it's not a woman's cup of tea but I'm determined to give it a go so please provide some suggestions and I can try it out. One thing to add: when it was heating the house but not water too good, I tried to turn the temperature to maximum to see if that helps. It didn't make a difference and the water was not more hot but only came for a few seconds and then cold again but since then I think it totally stopped. Is it possible that I damaged it by turning it to maximum? Any suggestions are very much appreciated.