Unfortunately Microsoft no longer offers open-to-all download of Win7. If you own the full version you can provide your key on their
download site but more likely you have an OEM copy or upgrade version so you would not be eligible.
If it came preinstalled on your laptop you can reach out to the laptop manufacturer for a copy but they usually charge around $100.
Sometimes you can still find the latest released version: Windows 7 SP1 Media Refresh (SP1-U) elsewhere on the web. Just be careful and check the hash code to make sure you downloaded a non-altered version.
Windows 7 Ultimate x64 English ... Size: 3,243,070KB, MD5 hash:
c9f7ecb768acb82daacf5030e14b271e