I recently upgraded Mandriva 2009 to Mandriva 2009.1 on my netbook and previously was using KDE 3.5 but switched to KDE 4.2.
I went into the Add/Remove programs and went to mandriva-theme to try to install additional themes. I'm not sure what I did wrong but now I'm unable to boot.

When I turn on my netbook it goes to the screen where it lists all kernels and then it goes to a black screen shortly after with text.
It has a lot of lines saying achi: Unknown symbol
Below that it says:
FATAL: Error inserting ACHI (/lib/modules/2.6.29.1-desktop-4mnb/ahci.ko.gz): Unknown symbol in module, or unknown parameter (see dmesg)
Waiting for driver initialization
stabilized: open /proc/scsi/scsi: No such file or directory
Could not resolve resume device (UUID=bcbd63d6-4109-4541-a9a4-40f7fb5211a8)
Creating root device
Mounting root filesystem
mount: could not find filesystem '/dev/root'
Setting up other filesystems.
setuproot: moving /dev failed: no such file or directory
setuproot: error mounting /proc: no such file or directory
setuproot: error mounting /sys: No such file or directory
Switching to new root and running init.
Splashy ERROR: Connection refused
Booting has failed
Splashy ERROR: Connection refused

That is the last that it says. I tried to reinstall Mandriva and select the upgrade option but then it just ends thinking it's installed. If necessary I will completely reinstall Mandriva but was wondering if there is something simple I can do to get it working again. Thank you.

I does look as if your system is not booting (e.g.: the message: Booting has failed) successfully, but there is one thing I want you to try. When you get to the last message, press the CTRL+ALT+F2 keyboard combination to see if you can get to a console login screen. If you can, log in as root, then run the following command:

telinit 3

This will shut down Xorg (if any part of it has started).

Next run:

MCC

This will start the CLI version of the Mandriva Control Center.
Navigate the menu list with the arrow keys on your keybaord (use the UP arrow key to enter the list, then the DOWN arrow key to navigate to the Display item. Use the TAB key to navigate to the OK button at the bottom then press the ENTER key to start the Display configuration applet. If the configuration looks OK, navigate to the Test item to test the GUI configuration. If you get a GUI screen with a combo box asking if you can read it, press the OK button to close the test. Back in the CLI, navigate to the OK button and press ENTER to save your configuration.

Execute the following command to start the GUI again:

telinit 5

If all goes well, you should get a GUI Log in screen. Log in.

When you shut down (or restart) the computer this session, you will get a dialog box warning you that a root session is running, click the OK button to shut down (or restart) the computer.

If you are unable to get to a console log in screen, you may be best served to reinstall Mandriva. I am sorry that you are having so much trouble . . .

Thanks for the advice. Unfortunately the Ctrl-Alt-F2 didn't work. Is there another way to stop Xorg? Unfortunately I'm not at a prompt so can't enter any commands at all.

I am unsure just what your trouble is at this point. It appears that your system is not completing the boot up since you do not get to a point where you can switch to a console log in screen.

If you have your /home directory on its own partition a fresh installation will not wipe out all your user accounts data because that partition (/home) is not usually formatted (unless you specifically format the partition).

If you have Mandriva installed on a single partition mounted at the root (/) of the file system, you should get a live! CD image, burn it to a disk, boot your computer from it, then mount your partition and copy any files you do not want to lose to a CD or DVD. This will work only if you have a CD or DVD burner.

If you do not have a CD or DVD burner, you should be able to get a USB flash drive suitable for this purpose. I got an 8 GB flash drive here for about $20.00 (US funds) recently and I saw a 16 GB drive for about $40.00. You will need one drive to which you will install Mandriva One and another to save your files on, so look for one large enough for a CD image (about 700 MB or larger will do) and another of sufficient size for your data files. All the Mandriva 2009.1 (Spring) iso image files are hybrid iso's that can be dumped onto a USB flash drive using dd in Linux or rawrite in Windows. You can also use rawritewin in Windows. These two Windows based utilities can be found in the ~/2009.1/i586/dosutils/ or ~/2009.1/x86_64/dosutils/ directory on the Mandriva ftp mirror of your choice.

In Linux, copy the iso image using dd. This example assumes the following:
The Mandriva One iso image file is in the user's home directory.
The image file is being copied from the user's home directory.
The USB flash drive is recognized as /dev/sdb
You will use the English version of Mandriva One with the KDE Desktop environment

In a terminal window (as root) execute the following command to copy the iso image to the USB drive:

dd if= /home/$USER/mandriva-linux-one-2009.1-KDE4-europe1-americas-cdrom-i586.iso of=/dev/sdb bs=8M

Notes: The above command can be used as is if you meet the criteria specified above.
$USER can be replaced with the user's directory name.
If you will be using a different Mandriva One CD image, replace
mandriva-linux-one-2009.1-KDE4-europe1-americas-cdrom-i586.iso with the actual file name.
/dev/sdb should be replaced with the actual device node of your USB flash drive.
If this process is to be attempted from Windows, I believe that rawritewin (or rawrite)
will work as expected, but if they do not, you can get dd for Windows at
http://www.chrysocome.net/dd

HTH,