Yesterday I tried to upgrade ubuntu edgy to feisty. It crashed halfway through and gave me this error message

Could not install '/var/cache/apt/archives/nvidia-glx-dev_1%3a1.0.9631+2.6.20.5-15.20_amd64.deb'


The upgrade aborts now. Please report this bug against the 'update-manager' package and include the files in /var/log/dist-upgrade/ in the bugreport.

subprocess pre-installation script returned error exit status 2

So I restarted the computer and booted up ubuntu. I went to see if I could try the upgrade again and in the update manager it said my system was up to date. So I checked to see what version I have and it said that I was running feisty, which is odd since the error message said that the upgrade was aborting and the uprgrade tool terminated. However, I can't find the new features such as "Enable Desktop Effects" in the System>Preferences Menu. I even tried to see if it maybe wasn't added to the menu in the System>Preferences > Main Menu option, but it wasn't listed in there. So I am thinking that I probably need to reinstall feisty just to make sure everything is running correctly. So how would I go about doing that? Is there a way to reinstall it without losing everything on my computer?

Depends, is everything in a single partition or have you got a separate home partition?

I think it's all in one partition

I would try running:
Maybe it will finish what it started.

No, it didn't do anything

Hmm, I'm afraid I can't think of any way to downgrade again. If you had a backup, it wouldn't be too difficult but I understand you haven't. I guess you'll have to use an "emergency prodecure".

btw, you really should have put /home on a separate partition. It usually doesn't matter whether you do but right now it does make a huge difference. You would have been able to reinstall only / and leave /home alone. That would have been far more convenient. If you ever consider starting over from scratch, I recommend you do put home on a partition of its own: 7 to 10 GB for /, the rest for /home.

Now, the best solution would be to copy or move your data either to cd/dvd or to another partition and to start over. Considering you had an accident doing the upgrade, it would be a good idea to download a feisty cd and do a fresh install. It's radical but failsafe - and it may well be the only thing that will help you get a fully functional feisty.

If you want to move your data to another partition but efty is taking up all the space, you could download and burn a gparted liveCD. This will allow you to shrink your ubuntu partition and make a new partition in the freed up space. Be careful resizing: if you resize too much, you risk losing everything. Next you can move/copy whatever you need/want to keep so you can format the efty partition and install feisty. Just make sure you don't accidentally install over your emergency partition. And do remember to make a separate home partition. It needn't be big: you can always use gparted to resize it later, maybe after moving back your personal data.