If your system fails, your data such as music, photos, documents may all be lost. Consider a backup system to protect your data using an external hard drive, web storage, etc this will help to mitigate this scenario. Ensure that if your system fails, you lose as little (or preferably none) of your irreplaceable or cherished personal data.

Tip: Correct way to backup your iTunes  https://support.apple.com/en-ca/HT201625  don’t wait till you have to re-install windows.