You can restart your VPS server is as follows:
1) go to ssh into your vps server and execute command reboot
2) If you can not login via ssh to your VPS, you can restart your vps with client-panel https://goodnet.com.ua/clients/, go to menu My Services, click on the properties of VPS server (white square with green arrow) and click on Reboot VPS server
3) if you have XEN vps server, you can restart it via VNC console