So when you boot up on to a terminal type.
sudo apt-get update
type your pasword, hit enter and let it do its thing.
sudo apt-get upgrade
if prompted type your password, hit enter and let it do its thing.
once is done running type
usually after running these command you would wish to reboot your computer
sudo is the 'super user do' command in Linux base operating system most of the admin tasks must be done from a super user level. So for you to perform changes , updates and installation of new program you have level up yourself with the root pasword.
If you just want to read the a configuration file or an error log you can do it with the cat command.
you must replace user from that command to the name of your user in your computer. Another thing is that if the file is big you will just see a bunch of text flying in front of your eyes. if the file is too big and you want to see it with pauses you type
cat /home/user/.xsession-error | less
then you can hit the space bar to see portions of the file. To get out of the cat command you just press the q key.
post result of your command line here on the forums using the quote tags by using [ ] like
[.quote]put your quote here [./quote] without the period thouhg.
good luck to you