natty, using 10.10 typed startx but screen goes blank

i have tried several times using wubi.exe (while inside windows) and while on the bootup on the CD to install side-by-side with windows and it keeps on returning to the command line. typed "startx" to go to ubuntu 10.10 desktop but it just goes blank... what seems to be the problem? my original OS is windows7 ultimate. my ubuntu installer is from ISO ubuntu-10.10-desktop-i386. i can see the ubuntu on the uninstall programs on the control panel so i just un-install it then proceed again. in fact, i was being asked to enter my user name and password on the command line when i specifically selected to to automatically log-on on bootup. fyi, have downloaded the ISO installer and made a CD installer. i am able to run ubuntu from the CD so i am under the impression that my ubuntu CD is a good installer. tried to make a USB installer and also able to run from the USB but when i tried to install from the USB, it also goes to the command line, so typed "startx" and still goes blank & does not go to the ubuntu desktop... what did i do wrong??