Can someone hack our PC/Laptop? If they do, how to recover our device? 

Check the behaviour of a device if you find something strange happening try to check system apps and current working apps may be some malicious app running in the background. If you find then install it and change your all passwords and set Two-factor authentication in account logins method. And click on trusted source links whether you get via messaging apps or from emails.

The Attacker hacks your System/PC/Mobile by your Mistakes; they send some malicious softwares, links, and many other possibilities to gaining access to the System there are a ton of methods which they use and attacking the Victims System.
Conclusion :
don't install any suspicious software, links, etc, and also the Cracked Items.
Recovering are devices are:
stop using the Internet at that time and open the task manager in windows, Go to details bar and check suspicious con host service or any install software services.

Yes, Hackers can Hack into your PC/Laptop and every other device you have. So, Recovery depends on the Impact that the particular attack has generated on your system. Also, Cyber Security Professionals are well versed in DFIR, i.e. Digital Forensics and Incident Response. Companies, Enterprises, Organizations have a Disaster Recovery mechanisms deployed at their IT Infrastructures. At a small level of an Individual, any IT Security Expert or Cyber Security Expert will be able to recover your data and system. Still, Diasater Recovery highly depends on the kind of attack performed on your order and the tools_&_techniques one implements to Recover from it.