Linux ATI HD3750 Drive Configuration Hangs

I'm not able to boot into GUI under Dell desktop system, which uses an an ATI HD3750 display card. The display only works with CLI and but when I type startx and get some sort of error or a black screen. How do I fix this issue?

There is no working proprietary or open source Linux ATI HD3750 driver exits. All, you can do is set it to vesa and use it for basic GUI display purpose. Boot into a single user mode and open the following file:
cp /etc/X11/xorg.conf /etc/X11/xorg.conf.bak.dec.02
vi /etc/X11/xorg.conf
Make sure Device section is set as follows:

Section "Device"
    Identifier     "Device0"
    Driver         "vesa"
    VendorName     "ATI HD3750 vesa"
EndSection

OR

Section "Device"
        Identifier  "Videocard0"
        Driver      "vesa"
EndSection

Save and close the file. Reboot the desktop or just type startx:
$ startx