Occasional failing to start up and BSOD

I'm having problems with my new computer, which I built it myself.

Basically, my computer fails so start-up sometimes (My motherboard produces a long beeep sound. GPU not running at all, but the rest of the components seems to be running - eg. USB, Ethernet etc).

Also, it will sometimes freeze while running some basic programs which are not really RAM or GPU demanding such as web browsers.

Finally, BSOD whenever I'm running some graphically intensive games (which theoretically, my computer should be able to handle.)

I've ran memtest86 for each of my ram and there were no signs of any ram defunct. Therefore, I'm speculating that the problem is either the GPU, CPU or the Motherboard itself. However, I'm not sure which one should I change. I've attached my 3 dump files, all of which seems to point to different sources of error.

Below is the specs of my computer:

Gigabyte H55M-USB3
Intel Core i3 CPU 540@3.07 GHz 3.06 GHz 4MB
4 GB DDR3 Ram (3.49 GB usable)
500 GB SATA Hard Disk Drive
450W Power Supply
Gigabyte GT 430 1GB PCI-E Graphic Card
Windows 7 Professional 32 bit OEM

By the way,

Intel Core i3 CPU 4 MB Cache 540@3.07 GHz 3.06 GHz

So is my processor running at 3.07 GHz or 3.06 GHz?

Please help me with this issue as the main objective of my new computer is to be able to run some new games which my old computer couldn't handle. With this issue, I couldn't even tell the difference between my new and old computer.

Thank you very much for your time

One video related, one a very unusual win login.

The video just needs the video driver re-installed using newest available.

The Login

If the error occurs during system startup, restart your computer, and press F8 at the character-based menu that displays the operating system choices. At the resulting Windows Advanced Options menu, choose the Last Known Good Configuration option. This option is most effective when only one driver or service is added at a time.