Note: If the virus does not allow you to access the internet, you need to download Malwarebytes off another computer and save the installation file on a flash drive and install it to the infected one.
Go to www.malwarebytes.org and download the free version of Anti-Malware (unless you want to buy it). Then go through the installation process.
When the installation is over, open up Anti-Malware.
You should see this window. Circle in 'Perform Full Scan' and as a percaution, scan across all your drives (check all drives in pop-up window).
Wait until the scan is complete and you should have a number of infections in bold red at the end of the scan. Click to see the infected items and press 'Remove All'.
Malwarebytes Anti-Malware will most likely prompt you to restart. This is normal. Do it and when your computer comes back on, PC Optimizer Pro and any other viruses should be successfully removed.