yes, reinstalling iTunes will do nothing to your media files.
that said, you should always have a current backup of your iTunes library !
get an external HD and use this app to keep main library and backup in sync:
SyncToy 2.1 is a free application that synchronizes files and folders between locations. Typical uses include sharing files, such as photos, with other computers and creating backup copies of files and folders.
Follow these instructions to completely remove Apple software
Then use free Ccleaner to repeatly repair your registry until it's fixed.
download iTunes again from Apple.
Your content will remain.