ok, here is a problem that I occasionally have (out of a variety of causes)

when I try to log in, it has a blank desktop with a terminal [and possibly another terminal and Firefox in some cases]. No panels or other things are found on Desktop. if I go back to the login screen, no longer are the installed desktops like GNOME and KDE available (I have not remove them) to be chosen at the sessions.

Now is there some generic way of troubleshooting this? [I am sure some of the (less than proper, especially for people who are not familiar with Linux) sequence handling lockups/freezes may lead to this so if these are put on the wiki sections it would be helpful.]

I am sure some of the (...) sequence handling lockups/freezes
What you mean to say is that something didn't work a few times and you decided to stop being patient and power-reset the machine?


when I try to log in, it has a blank desktop with a terminal
If you are sure you properly installed your DE's then that's a symptom of the system not being able to find any preferences or start your preferred DE and it then falls back to failsafe mode. What you described above (if I got that right) breaks syncing data on filesystems and could well leave the system in an unstable or broken state. Now there's two approaches really. With GNU/Linux it's almost *never* necessary to reinstall software if something doesn't work, however fixing it takes time and patience.

If this was a (relatively) fresh install you broke, deciding to reinstall won't cost a lot since you didn't do much already, will save you the frustration of battling it out with all sorts of commandline horror and everything should work again. That's doing things "the wintendo way". If you decide to do things "the Linux way" you should first check your X11/Xorg logs (/var/log/X*.log) for errors (check for "WW" and "EE" lines), then check your system log for errors (/var/log/messages by default) and post anything that looks like related errors here and we'll take it from there.

In the meanwhile please fill in your User CP info so we know what distro+release we're talking about.