Turn Bell Boots

At the moment my computer will only start 2 in 5 times I boot it, I turn it on, get the packard bell screen then nothing. Doesn't seem to be doing anything with the hard drive either, as the light for it never flashes when
it does this

How can i fix the problem before it gets worse?
Well Packard Bell is a huge name in the UK just walk into a computer store and you will see so.

By the way that doesn't answer my question