Mac applications still not responding after multiple attempts to fix

Hello you wonderful people of Apple.

I'm a university student using a MacBook Pro (early 2011) that in the last week has started falling apart on me. Before last week I had no big issues.

The first thing I noticed was one week ago. I tried to save a file in TextEdit I had been writing code in. When I hit Command+S to save, I got the Beach Ball and no save dialog ever appeared. I ended up force quitting Finder, but after that I couldn't get it started again. I restarted my Mac.

This happened three more times whenever I wanted to use a Save, Open, or Print Dialog. Each time I would need to restart, which would fix the problem for about 6 hours.

I went online and found instructions for deleting the .plist files, which is supposed to help but did not help.

The next thing I noticed was Time Machine stopped backing up on a daily basis. It was then (and still is now) stuck on "Looking for backup disk..." when I attempt to connect to my Time Machine to back up. To remedy this I tried going to System Preferences and into the Time Machine screen, then clicking the "options" button to see what would happen. It froze. I haven't yet been able to get this to work. Each time I must end the process in Activity Monitor.

Starting three days ago, random base applications have begun freezing upon exit or normal execution. iTunes does this most often (because I use it most often, I think). As I type, this is happening with iTunes, Console, TextEdit, and System Preferences. The only way to get them working is to forcibly restart the computer. When I try to restart with the simple "restart" button in the top-left, it does not execute because Finder stops responding.

I have verified and repaired disk permissions and verified and repaired the disk itself twice. Earlier today I reinstalled OSX from my most recent Time Machine backup, now a week old.

I'm not sure what my next step should be. Note that I cannot use Console whatsoever. It does not show a screen when open.

Things I have noticed:

-Safari and Safari Web Content are together taking up 700MB Real Memory. I have no previous statistic to compare this to, but it seems high.

-I've been monitoring processes on Activity Monitor for days, and nothing horrible seems to be popping up. Average User CPU%: 7, Average System CPU%: 11 (by my guess)

I have used ClamXav to check my system; no problems. I used EtreCheck to check my system; the first time it told me a process took 99% of CPU, and I copied the info down but I can't find that file anymore (it was not backed up to Time Machine). Subsequent runs have proven to freeze EtreCheck.

I'm lost as to what to do next. This is a great computer, but I've always felt it's a little slow for 8GB of RAM. Is it possible I have a system leak? Or a non-detectable virus?

So far the only things I can do reliably are surf the web and... that's it.

Thanks in advance for any help!

I tried to attach a screenshot of my Activity Monitor showing 5 applications frozen, but Preview froze; trying to save it in Paintbrush, the old "no save dialog" problem occurred (see above).