Built my new computer/need help!!

Here are my specs:
Motherboard
BFG Tech nForce4 Ultra PCI Express Socket 939-AMD Athlon 64/64FX
(DLed and installed latest chipset drivers)
Processor
AMD Athlon 64 3200+
BFG Tech NVIDIA GeForce 7800GT OC 256MB GDDR3 graphics card
Connectors: Dual DVI-I, HDTV, VIVO
Included in box: DVI-I to VGA dongle
HDTV dongle
VIVO dongle

(Dled and installed latest drivers)
http://www.bfgtech.com/7800GT_256_PCIX.html
Monitor
Samsung SyncMaster175v 17" Analog flat panel LCD

Paid a nice sum for this setup. However, this is where I need some help.
Iam running WinXP Pro, and on boot up, my system is not recognizing the monitor, eventhough it's connected to the graphics card via DVI-I to VGA adapter. I've had to bring out an old CRT monitor and connect it to the computer where it runs fine. I adjusted the settings (refresh rate, 800x600 resolution, etc) and turned the system off. Then I reconnected the LCD mon. in hopes that it would fix the problem. NO
SO I call Samsung and the Tech Level 2 guy tells me to try and "hotswap" monitors, so I disconnected the CRT and connectedthe LCD while the computer was turned on, and it worked. I can see just fine on my LCD monitor, given that its hotswapped. I go into nVIDIA Desktop Manager settings and it tells me that the Analog Display is disconnected. However, I am typing away and seeing everything on the screen.
Right now,I can adjust refresh rates, resolution settings on the LCD flat panel monitor and they work just fine, as long as the LCD monitor is hotswapped. But as soon as I reboot with the LCD monitor connected to the comp, it goes all the way up o the Windows Splash screen and then goes blank, with the monitor power light blinking off and on.
I thought the DVi-I to VGA adapter included in the graphics car box allowed for the DVI-I signal to be compatible with analog monitors. Can anyone help me, cause I don't want ot spend another 400 bucks on this computer.
Any help??

 

By pressing the ''F8" button, you should be able to run Windows in some kind of VGA mode, it doesn't load vga drivers and stuff. Rescued me a few times.
Maybe you'll find your problem, this way, if your monitor works this way its probably the driver making the problems.