Similar problems might have been reported already for your computer model in our [[list of known issues about Tails not starting at all|support/known_issues#pc-not-at-all]].
<p>Take note of the changes that you apply to the BIOS or UEFI settings. That way, you can revert the changes if they prevent the computer from starting on its usual operating system.</p>
Edit the **Boot Order**. You might see an entry for **Removable devices** or **USB media**. Move this entry to the top of the list to force the computer to start from the USB stick before starting from the internal hard disk.