Here are a few potential things you could do to troubleshoot why your internet isn’t working on your office computer:

1. Check that your network connection is active
2. Restart your computer and your router/modem
3. Check for any loose cables or connections
4. Log into your router or modem’s web-interface to check the status
5. Check for any messages displayed on the network status page of your computer or router
6. Check with your ISP if your account is active and your service is still working
7. Scan for any viruses or other malware on your computer