いつもお世話になっています
nvidiaのビデオカードを使っていて、今までプロエタリドライバを有効にして使っていましたが、これを無効にしようと思い
システム管理→制限付きドライバの管理　からnVIDIA accelerated graphic driverを削除して再起動したら
Xがエラーで起動せず、コンソールモードで起動してしまいます。

startx してみたら
X.Org X Server 1.9.0
Release Date: 2010-08-20
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.24-28-server x86_64 Ubuntu
Current Operating System: Linux asti 2.6.35-27-generic #48-Ubuntu SMP Tue Feb 22 20:25:46 UTC 2011 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.35-27-generic root=UUID=9ef33bf3-e4b5-4c18-96ac-91a5b40d5341 ro quiet splash
Build Date: 09 January 2011  12:14:27PM
xorg-server 2:1.9.0-0ubuntu7.3 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.18.4
    Before reporting problems, check http://wiki.x.org
    to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
    (++) from command line, (!!) notice, (II) informational,
    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Thu Mar 10 21:25:53 2011
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
(EE) NV: Kernel modesetting driver in use, refusing to load
(EE) No devices detected.

Fatal server error:
no screens found

Please consult the The X.Org Foundation support
     at http://wiki.x.org
for help.
Please also check the log file at "/var/log/Xorg.0.log" for additional information.

ddxSigGiveUp: Closing log
giving up.
xinit:  No such file or directory (errno 2):  unable to connect to X server
xinit:  No such process (errno 3):  Server error.

とエラーメッセージが出ます
Xorg.0.logの最後の方には
[   284.052] (--) using VT number 8

[   284.053] (--) NV: Found NVIDIA GeForce 8500 GT at 01@00:00:0
[   284.053] (EE) NV: Kernel modesetting driver in use, refusing to load
[   284.053] (EE) No devices detected.
[   284.053]
Fatal server error:
[   284.053] no screens found
[   284.053]
となっています
なんとかXを起動させたいのですがどうすれば良いのでしょうか