Few MBP problems/issues/questions

Hello everyone,

I'm two weeks old swither. I've using windows for more than 10 years so I'm still getting used to Mac. I'm using Macbook Pro February 2011 model, 13 inch, low-end model. Here's few things bothering me..
1. After updating to 10.6.8. my Mac is noticable slower. Yep, I've restarted it few times.. Also, almost all Apple-made apps are crashing after open. So, I can't use Safari, App store, Pages or Garageband(even Dashboard!). I want to fix that, fast!
2. There is gesture I can't find how to disable. When fast moving cursor to upper left corner it's like four fingers-up, and when doing this to right corner it's like to four finger-down. Sometimes it's activated with no purpace and makes me problem.
3. I'm in Youtube's HTML5 program and sometimes it tells me I need to down Flash player. What's his problem?

Crashing problem from 1st question is most bad for me and really sucks! I want to fix that as soon as possible.
And yeah, I updated everything using Software Upadate..

Thanks!

 

Thanks, this helped!

Anyone knows answer to 1st question?

 

Yeah, really was bad. Actually, I needed to down 10.6.8 Combo update and that fixes everything. I done it and everything is as old! Actually, my MBP seems to be a bit slower
I found this at apple discussion forums. I should go check there firstly for my problem, aren't I?

Thanks for help!