What is wrong with my user account?? Why do I get kernel panic when restart

Hi there. I got Leopard and was quite unhappy (don't think it was meant for a powerbook). So I started using Tiger again, and I flip flopped once or twice after the update came out for Leopard, thinking/hoping it would fix my problems. It didn't. I have given up on Leopard.
But, now Tiger seems to have a few problems of its own. I get the kernel panic when I restart my computer (telling me to restart), so I have to hold down the power button to turn it off and then turn it back on. Not a big deal, but if it shouldn't be doing that, I don't want it to, ya know? Never did it before Leopard.
My user account seems to be dysfunctional when it comes to downloading plug-ins for safari or firefox. I had to create a new user account and download the plug in from that account and then drag it into the HD to use it on my user account. I repaired disk permissions and booted from Tiger and did the same thing on there. After that, my user account is still not able to download that plug-in without getting errors (256)?
Is there a way to do a reinstall of Tiger from a blank slate, and be sure there won't be any problems?
Thanks!

Leopard will work with your Powerbook, the question is, is all your software and hardware ready for it?
Is there a way to do a reinstall of Tiger from a blank slate, and be sure there won't be any problems?
You can start from a blank slate, but if you have a hardware problem that started to generate itself, a blank slate won't solve it. It is called an erase and install. The first thing to do is backup your data*:
http://www.macmaps.com/backup.html
Once that is done at least twice, we can start looking at solutions for kernel panics*:
http://www.macmaps.com/kernelpanic.html
- * Links to my pages may give me compensation

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                  if ( fine == suspect ) {
                    System.err.println( "is it real?" );
                if ( fine != anotherFine ) {
                  System.err.println( "should never be printed out" );
        }.start();
      private void run() {
        while( true ) {
          synchronized( lock ) {
            ++iterations;
            fine = ! fine;
            anotherFine = ! anotherFine;
          suspect = ! suspect;
          synchronized( lock ) {
            lock.notify();
      public static void main(String[] args) {
        new VWC().run();
    }

    jalligator wrote:
    Steve, thank you very much for the comprehensive explanation. Sorry, actually I wanted to see how many developers are aware of volatile variables specifics and how many of them are open minded. Not sure how this question addresses either of those questions.
    This snippet is a stripped down version of production code. Developer relied of volatility, inverted boolean in one thread and expected to see the change right away in other thread. Unfortunately value propagation takes time (not a milliseconds though), Without volatile, yes it takes time. With volatile, no, the updated value is seen instantly (though accessing the volatile variable is less efficient than accessing a thread local variable because it has to retrieve it from main memory first and then use it...)
    so second thread sometimes misses value change; it happens approximately once per million on my box. That is not what is happening in your example code. It is not that suspect is being changed and the second thread misses the change. What is happening is approximately once per million times through your loop the value of suspect is being switched between the two if statements. Sequentially your computer is doing this:
    1) [Thread A] if ( fine != suspect ) {
    2) [Thread A] System.err.println( "be aware: " + (++failures) + "/ " + iterations);
    3) [Thread B] suspect = ! suspect;
    4) [Thread A] if ( fine == suspect ) {
    5) [Thread A] System.err.println( "is it real?" );
    I found that bug in production code and proposed to use synchronized blocks at least. However, all team members said volatile variables work perfectly. I typed this snippet as a concept proof, however, nobody took a look and f course nobody tried to compile and see how volatile vars work in reality. I would ignore this issue unless I had to fix this bug. However, they still disagree and claim there is some other problem and I have to solve it. I am absolutely out of options now; I found the bug, however, they ignore my finding and demand me to find something else.Edited by: stevejluke on Jul 5, 2008 10:10 PM

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