I recently installed version 14.04 on ubuntu laptop and sadly regretted it. Is it possible to downgrade back to 12.04 and if so, how?
@parto links something usefull
What I want to point out is that if you have different partitions for /(root) and home you can boot with live cd (12.04) choose something different in the options to manually decide your partitioning .
Mount everything as before home to home, swap to swap and root to root ( / ) but you have to format this system partition ( with the ubuntu version you choose )
With this you still have to get all the apps and packages you need but some of your customization will still stand because for example firefox and thunderbird (.) hidden folder exists in your home directory .
If you don't have partitions and you decided to make one big piece for everything you must already have a copy of your essential files , in that case make a new installation with partitions to avoid this in the future .
Don't forget to back up of your files , just in case .
There are some very good guides for partitioning take a look if necessary .
I hope it helps