Resolution of my X server config fault

My PC type is DELL vostro 200. Its have a Integrated Graphics card which type is 82G33/G31. And here is a PCIEx16 card slot on the motherboard. so, I install a PCIE Graphic card so as to improve it's efficient. but unfortunately, the card seems some broken. it can't work well. I uninstalled it. Then its comes some problem: I can't get a right xorg.conf file. Because the current file is generated by the NVIDIA installation program. (I remember its said he had made a backup file when installing NV driver. but I can't find it everywhere.)

Now I can't get a right configuration file for the integrated graphic card. so I must try to modify the current xorg.conf manually. I read the xorg.conf manual. but it's helpfulness. doesn't work still. Here is some information that I think it's important:

cat /var/log/Xorg.0.log | grep EE

(EE) No devices detected.

google it! I found a little information. disappoint!

Reread the /var/log/Xorg.0.log. There are some another information at the end of file:

Fatal server error:
no screens found

google again! I get the useful information at www.x.org site(look here)
Steps success for me:

sudo X -configure

but here is some warning seems about my ~/.Xauthority file. so, clear it and the relation files "~/.Xauthority-c", "~/.Xauthority-l". Then rerun the command. success!