Sewing machine - aargh!

[tigana]

Recently got my sewing machine fixed (finally) and was preparing self for orgy of clothing alterations, patchwork cushion cover making and re-use of old clothes to make funky trousers for ds.
Instead it sewed fine for about 10 minutes, ran out of bobbin thread, I replaced that and now it is merrily looping the thread round and round and round and round the bobbin case/holder instead of sewing.
Argh!

Any idea of what I have done?

Have you put the bobbin in the holder the correct way? If yes have you pulled the thread through up to the top?

{sorry if this sounds patronising}

Not patronising. I did wonder that myslf, as it has been a while, but I have wibbled the bobbin thread through the little gaps in the bobbin case/holder thing and then used the hand-wheel thing to move the needle down and up to pick up the thread...which I think is how I used to do it...
Could I have put bobbin in upside down or 'wibbled' in the wronmg way?

To see if the bobbin is in correctly, take it out and lie it on its side. The thread end should be in the top left position and unwinds the bobbin anticlockwise when pulled.

Once its like this pick it up as it is and drop it into the bobbin case. Once you've "wibbled" the bobbin should still turn anticlockwise.