Having problems since upgrade. Ideas welcomed

I upgraded my 12"PB 1.33 G4 768 mb ram to Tiger about a month and a half ago. I say upgraded, but I attempted an upgrade and it frooze about 75% completed. Not to big of a deal. I had my documents saved elsewhere. I bought the notebook new in Feb 05 so not to much has built up on it. Well after that I decided to just wipe it out and start over with Tiger. I had to attempt the install a couple times before it completed. Since I have upgraded I got all my stuff reinstalled, but now, almost daily Firefox will crash and have to restart several times, Safari will crash periodically, widgets will crash, etc. Even OS X will freeze periodically and I have to power off. I have had a couple kernel panics that required a restart. I have repaired permissions many times. Anyway, I really don't know what to do next. Under Panther the system was very stable, under Tiger is has been very unstable. Please give me some ideas, I am becoming frustrated at this point.

Thanks for your help.

I bought my mini the day Tiger was release, so it came with it and I've had similar problems as well. As for the Kernel Panics, do you have any external devices connected to your PB when they occur? Also, what apps do you have installed? Those could be some possible explanations. To see if anything installed or connected is causing the crashes and freezes I'd suggest doing another clean install. Afterwards, just install your apps one at a time and see if any are causing issues (I know it's time-consuming but doesn't hurt to try). If that doesn't solve your problems then I'd suggest you go down to your nearest Apple Store or give them a call to see if they can help troubleshoot your problems.