Hey there, Dominykas_5.
Usually this error is associated with either with an HDD issue or a virus. It's good that you still have access to your important files while the drive is connected to another computer. So I'd recommend that you update your antivirus programs database (on the 2nd computer) and backup the files from the problematic HDD. Don't scan the problematic drive for viruses just yet, because if it turns out to be an HDD issue, it might be a mechanical fault and all sorts of scans or tests might make things worse. That's why it's important to backup your data first.
After you've backed up the information you need, go ahead and download the HDD manufacturer's diagnostic tool and run the tests on the drive, to see what's the situation with it.
Oh and one last thing, you could give it a try with a different SATA port and different cables, to see if you'd be able to boot to Windows properly.
Hope that helps. Please let me know how it goes.
Boogieman_WD