You would need to contact HP Suoport, although I doubt damage caused by rats would be covered under warranty.
From a post by Sunshyn2005, to contact HP Support see the following link to create yourself a case number, then call and it may help speed up the call process:
Step 1. Open link: www.hp.com/contacthp/ Step 2. Enter Product number or select to auto detect Step 3. Scroll down to "Still need help? Complete the form to select your contact options" Step 4. Scroll down and click on: HP contact options - click on Get phone number Case number and phone number appear.