I was following some "guides" on how to clean my system and have cleaned it so well that it doesn't work anymore. Example: in synaptic, I completely removed all packages in "Not installed: residual configuration" and a ton of other packages I "don't need".

I know this has probably been asked a trillion times but I really need to find out how to get back to the working OS I had about two hours ago. One hour of googling has not helped me, so I am asking here.

When I start Ubuntu, usually nothing happens for quite some time and then tty1 starts. I can log in normally, but I don't know how to proceed from there.

I can do:

less /var/log/apt/history.log

and get a log, but I don't know how to get started with this...