iTunes is unstable... OSX 10.4.6 Build 8I127

[Sciamo]

I have been having a LOT of trouble with iTunes. Pretty-much, it locks up and won't restart (even with force quit) and I have to restart. I double click to open it - that's when it locks. Sometimes it does work - sometimes not.
I've reformatted the whole drive. I've removed iTunes with Apple's help, and reinstalled it. Same thing.
Any ideas?

G5 Dual 2.0
300GB Hard Drive (system)
750GB Hard Drive (music)
19813 tracks (Apple Lossless) at 529GB (sick, I know) - no MP3, all ripped from my CDs http://www.shubert.net

Is the problem the size of my collection?

Thanks for your help!!!

[Mystic Gohan]

prolly I only have around 3400 songs in my library, and no probs. nothing like you have said.