spaces stopped working

Can still use spaces by clicking on top menu bar, but none of the keyboard shortcuts work and hot corners also does not work. Doesn't work on external keyboard or on macbook keyboard. This happened after the screen saver activated once. May have something to do with it:

http://74.125.47.132/search?q=cache:-rZ7xMNSZRoJ:forums.macrumors.com/showthread.php%3Ft%3D514794+hotcorners+stopped+working&cd=2&hl=en&ct=clnk&gl=us&client=firefox-a

keyboard messed up in xournal

Keyboard produces garbage in xournal when I try to write in the margins of a paper. Makes xournal completely unusable.

Crash

Computer froze after I plugged in monitor extension, external mouse and external keyboard.

Partial crash?

I feel like my mac crashes a lot. I'm not really sure how often it actually happens, so I'm gonna start to take note when it does. Just now, spaces stopped working and I although I could still use the internet, could not move abut to other spaces. So I had to restart and loose the simulation that I was running. Also, it took like 4 tries to restart- the apple screen would come up and the little spinner below the apple would freeze, and I would have to restart again. Finally it restarted and seems to be OK. Annoying.

Switching spaces when opening a new app

If I want to, for example, open a PDF from the internet, it will open in another window which already has preview running. This is really annoying. Especially since I am using 16 windows right now to juggle my dissertation and computer simulations. I didn finally realize that I can assign certain applications to open in certain spaces, which is quite helpful- I usually move firefox to space 4, itunes to space 8, etc. But i haven't figured out how to fix this other issue, even though I have unchecked the box in system preferences that says "When switching to an application, switch to a space with open windows for the application."

Time machine stopped working unexpectedly

Was working great for a while. Then it stopped. I think that was because of the server computer- it just couldn't read the drive. Then it worked again. Now it has stopped again with an error saying that the drive is not writable. I don't know what this is about- since I spent all that time making it writable and then it worked for like 5 months. Haven't had time to work on this because I've been too busy writing my dissertation which really really needs to be regularly backed up.