New build with 64 bit vista problems

I was wondering is repetitive freezing, bsod's, and failure to boot are normal with vista. I just built this system, and it usually will start windows fine (unless my external hdd is plugged in) but it often freezes in the first few minutes. I also bsod'd when i tried to install video card drivers and antivirus, one time for each. I installed mobo chipset drivers, video and sound drivers, and ethernet drivers. That was about it, and from the beginning the system has been crashing and such. Is there something I need to do to configure my hardware still for stability? I would think a system with a clean OS would run smoothly. All the drivers I installed were for 64 bit windows vista.

AMD Phenom X4 9950 BE
250 GB Seagate HDD
3x 1Gb Corsair 800MHz RAM (1 was bad, so 4Gb after the RMA)
ASUS M3A32 MVP Deluxe mobo
nvidia 9600GT

Any advice would be appreciated, thanks.

PSU is an Ultra 500W. Not the best I realize, but I was hoping it would be adequate to start. I'm looking at getting a new one soon. Could that be responsible for these symptoms?

I guess I didn't realize the PSU was so important and could effect the computer like that. Next time I won't skimp on that part of the budget. I'll do memtest with the bootable iso tonight.

I initially changed ddr2 voltage from 1.8 to 1.9 when starting out, but every time I restart it returns to the default setting. Is there a way to make it more permanent? I believe the mobo has a utility that runs in windows that allows this to be changed, but I think that has to be reset every time the computer is restarted too.

Mine usually would show the windows loading bar, and then go black and never move if my usb hdd was attached. Couldn't get windows going in safe mode or anything till I finally figured it out.

It did blue screen when I attached it after installing daemon tools, but I went to a restore point pre-installation and decided that software was a lost cause.

It maintains the time. I didn't reset much else so it's difficult to say. The timing on the ddr2 I defined manually, and it resets to auto when i restart just like the voltage does. The boot order also remained changed, as in I modified it from the default and that change is still in effect. I don't believe I changed anything else.

Yeah, I'll run memtest after work tonight, then do cpu-z. Thanks for helping.