Vista dosn't shutdown

Iam having a problem with Vista shutting down. I go to Start > shutdown and it does all the stages and then it says "Windows is shutting down" and my computer makes the noise it always makes when XP shuts down (I suppose its made from the fans stopping and the harddirves stop spinning) but the screen stays there still saying "Windows is shutting down". In the end I just push and hold the on/off button. Is anyone else getting this problem?

DId you ever get this sorted?

ermmmmmmmmm, i havn't tired doing anyhting. But i've been on hoilday and havn't been on vista yet. Ill have a go later. It seemed to be intermitant (sp?)