I have read this post My computer boots to a black screen, what options do I have to fix it?

UBUNTU 12.04 works well with livecd but fails to start after complete installation, black screen with a blinking cursor. I tried holding shift key and edit grub options but holding shift did not do anything. I give up, any suggestion. I have built in intel graphics card and an nvidia card in PCI. I have tried by removing nvidia card as well. All I see is a black screen with a blinking cursor. My system is Dell optiplex GX260 with 1GB ram and 2.4 GHz P4 processor