New system, lots of problems

Hi community,

My (fairly) new system is unpredictable and a little unstable, and I need some suave gentlemen like yourselves to help me troubleshoot it.

Specs
Motherboard
Video Card
CPU is an Intel i7 920
RAM (3 sticks instead of 2)



Symptoms:
-BSODs: These happen sporadically, the file given is more often than not an ATI file of some sort, but not exclusively. These may be more frequent when/after I've changed the amount of RAM to or from 6 gigs. It's kind of hard to tell with how completely random they are. Sometimes I'm playing a game, sometimes I'll boot, go to the kitchen, come back and find it rebooting.

-Computer does not respond well to having all 3 sticks of RAM in. Sometimes it'll boot recognizing 6 gigs (and probably BSOD), sometimes it'll recognize 4 gigs, and sometimes it'll recognize 2 and run like ***.

-Fragmented Cursor: I have a dual monitor setup (1920x1080 Asus and a 1280 x 1024 Sony). Sometimes the vertical lines in the cursor will fragment and jumble. This only happens on the Asus monitor, and requires a reboot to fix. I've updated the ATI drivers a billion times, nothing changes.

-GPU Fan: Makes a fairly loud whirring noise on medium loads (maybe 25-45% fan speed). Happens on boot, over time it will go away even at those loads.

-No Disk Detected: I get this error message just before booting from the HDD. So it obviously is detected. So far it doesn't seem to mean anything, but it's odd.



I'm not a very good troubleshooter, so I appreciate any help you guys can offer.

Thanks