Vista - Working crash

I recently purchased the following system:

Gateway FX541S
(Although I was not told ahead of time, I believe the unit may be a
rebranded Acer)
Intel Core2 Quad
Q6600 @ 2.40 GHz
3 gig Ram
32 Bit system
NVidia 8600GT video card
Windows Vista Home Premium

This is my first experience with Vista and overall I really dont have a
problem with the OS. But I do have a couple major glitches.

I can be working with an open window (it doesn't seem to be any specific
program), click a button and the screen I am working on goes grey making the
window no longer accessible. I get the little swirl where my pointer used to
be showing the item is working and sometimes I get the (Not Responding)
message after the title at the top of the window. I also sometimes get an
error saying the program has a problem and Windows is searching for a
solution. The solution is never found. Sometimes I can close the window but
usually it crashes the comp and I have to restart.
Has anyone heard of this problem before?
Thanks...gary