Hello there,
You could go into safe mode & hit reset this laptop if you're on Windows 10, by using F8 or Shift + F8.
When you're on an older version of windows you might want to do the following:
- Burn any Windows software onto a disk.
- Insert the disk into your laptop.
- Once you come on there, go click next on most the options.
- When it asks you for what kind of installation, press custom.
- Select the hard drive you'd like to use (recommend formatting it).
& just wait for the installation to finish, as soon as it's done, you'll be able to use the laptop again.
Good luck