Computer crashing--Need help

My computer is almost constantly crashing now, and I need some serious help. I basically have three things causing this:

Problem 1): When my computer starts, several programs ask for permission if they can access the Internet, act as a server, etc. When that happens, it will, the majority of time, crash immediately. I always give these programs the permission to do so, and tell them to remember to access automatically next time. They do not, and always ask for permission, which in turn always crashes my computer.

Problem 2): Now this doesn't happen all of the time, but does happen occasionally. When my computer starts, and I click the Mozilla Firebird icon on my desktop (or any other program for that matter), it will not launch the program. Instead, it will pull up the "Properties" box for that program. Now, I can launch the program if it was one of my most recently used programs, since it will be in my start bar. However, when I do that to launch Firebird or Explorer, the text size changes when I scroll, instead of moving up and down the page. Also, the keyboard will not work in Yahoo Messenger or any other program. Eventually, this usually goes away.

Problem 3): This one is the most rare, although it does happen. I also use AOL Instant Messenger, and usually it works really well. However, sometimes when I logged in and the program is running, but not being used by me, the AIM main window pops up for no apparent reason, which crashes my computer.

Those are the three major problems I have. I have ran Hijack This, SpySweeper, Ad-Aware, Search and Destroy, etc. I have deleted Kazaa and other trouble-causing programs. What should I do?

Thanks in advance for the reply