Vista - strange Black Dots

Hi there,
I've just received my laptop back from the repair center.
My Geforce 8600gt was broken so they changed it with another one.
Since my previous installation was still on I suppose that it would be al ok.
the only thing is that I get strange black dots at my windows on the side of my sidebar and if you look really close also in the taskbar.
If i move the window the dots move with it. if i click on one window the dots change a little position, but remain still there. If i move my mouse over the sidebar they dissapear on the sidebar. but as soon that i move my mouse somewhere else they come back.
strange thing is also that i can't change my resolution more than 1024x728.
i tried to disinstall my graphic card but windows won't let me. as soon that i press disinstall, windows installs it automaticly back it.
i've tried with new drivers and also the old one but nothing changes.
I would be really happy for any help.

To temporarily stop Windows reinstalling hardware immediately after you've removed it try this.

Right-click Computer and go to Properties.

Then click System Protection at the left and OK any UAC prompt.

Click the Hardware Tab.

Click Windows Update Driver Settings and select one the two last choices, Ok and exit.

Try removing the Display Adapter in Device Manager and reboot. See if that helps as Windows should offer to install a driver when you try to update it, if not go to nVidia and get the latest driver for your card.

You also might want to make sure the card is seated properly in its socket and the connectors are OK.

Otherwise I would go back to whomever did this and demand a fix.