I had iTunes running without problems. Was notified there was an update (126.96.36.199). Took it, it installed, after that, was never able to run iTunes again. I got an error message (can't remember message number now) that a component was missing. Tried installing several times again. The software always wanted to repair. Successfully completed installation. Same error message over and over. Removed qtime and itunes, tried to install 188.8.131.52 again, and it fails almost immediately with NO error message. The error says:
*************** The installer encountered problems before iTunes could be configured.
Your system has not been modified. To retry these operations at a later time, please run the installer again.
Click Finish to exit installer.
Finish button is only active. **************
I removed all entried I could find in the registry to Apple, iPod and QuickTime, and tried again... same thing.
Downloaded iTunes setup several times to make sure...
Same thing. Luckily, my iPod id still fine but I have NO software to do anything to it.