My computer with debian8 KDE would not start in graphical mode anymore only in command line. First I got message PC8 login: [ 6.636955] USB 3-9: 3:1: cannot get frequently at ep 0x82. If I disconnect my Webcam I don't get the message anymore but still doesn't go to Graphical interface, I get on the screen:
Debian GNU/Linux 8 PC8 tty
PC8 login:

I should mention that I did add one line in /etc/fstab to install an extra hard drive but it Hd worked initially. When I restart the computer next day I got this problem though. I then restored the original /etc/fstab (removed the line that I added then shut down the computer and removed the extra drive). Now all is as it was originally but cannot get the graphical interface as described above.

Any suggestion? (beside reinstalling Debian from scratch?)

What is the output of:
What happens if you run:

It sounds like it may depend on the /etc/fstab file - For instance, using device names is not the thing to do unless you really only have one disk. Either use UUID= or LABEL= options (and with LABEL, be sure the filesystem you want on the mount point is labeled.

It is possible the wrong disk was mounted by default.

"would not start in graphical mode anymore only in command line. "
I'd assume something has changed. Did you change anything.

The /var has logs and maybe other places for video/window manager.

Check the runlevel.-

http://www.tldp.org/LDP/sag/html/run-levels-intro.html

When you edited the /etc/fstab file are you sure you had the correct UUID number of the other drive?

If you hosed your KDE DE you can always reinstall it.-