XPS8700 - Can't end crashed program in Task Manager + Shut down problem

Hi,

A couple of months ago I've bought a Dell XPS8700. Before I had an Inspiron laptop and must say I've always been a happy Dell customer but now I'm somehow dissapointed…

First problem was when I’ve tried to shutdown the PC for the first time. My screen went black but the fan kept turning and the computer didn’t shut down at all. By searching on Google I’ve found a solution: http://en.community.dell.com/support-forums/desktop/f/3514/t/19540744 . It did the trick and I was happy again.

However… When a program crashes and I try to end it with Task Manager (end process), it does nothing at all. It won’t end or close my task! But the big problem is: when a program has crashed, I can’t shutdown my computer. Same story as here above: screen goes black and standby but the fan keeps turning. So everytime an app or program crashed I have to hard shutdown my PC by holding the powerbutton for 10 seconds. I can imagine this is not healthy for my PC.

Please help me before I ruin my computer! Thanks in advance