How to check for missing system files in Lion, and recover them?

Question

I've recently been having some troubles with iTunes (in particular, when I tried to update my iPhone 4 to iOS 5, it error'd out and bricked my phone instead), and I suspect these problems may be due to missing and/or corrupted library files in my System libraries.

Given that, is there any easy way to verify that the correct system files are present on my Mac OS X Lion boot partition, and if they aren't, to recover any missing or damaged ones?

(I could try reinstalling Lion, and then recovering from my latest Time Machine backup, but it looks like Time Machine backups include the System folder, which suggests to me that the damaged state of the System files might be reintroduced as part of the Time Machine restore!)

Answer 1

You can just perform a Lion installation over you current one - just watch out not to delete your user files (I think this is even default).

Mac OS X installation will replace all your system files and correct their owner and rights, but will not touch Applications, Documents, Settings, ...

It's kind of the "repair installation" Windows XP had, but sadly Vista and 7 lost.