Windows 7: My Windows 7 is slow, and under attack

The place where I work has three Windows 7 installations. There is about 50 Linux/Zorin OS 5 installations, 5 Red Flag Linux installations, and 4 Ubuntu installations. All machines are standard, i. e., everybody has to use the same configuration. The problems with Windows 7 are

(1) It is very slow. In general, in the same machine, it is 5 times slower than Zorin or Red Flag. When I try to uninstall Microsoft software (for instance, when I try to uninstall Visual Studio) it takes at least a couple of hours to answer the uninstall command.

(2) I thought that virus was a thing of the past. Zorin people told me that I didn't need to worry about virus. I hoped that Windows 7 would be immune to virus as well. People here tested the hypothesis in one of the machines and in a couple of weeks it was virus ridden.

(3) When one install an antivirus in Windows 7, it becomes even slower. What is worse, the antivirus report a lot of false positives.

I contacted Microsoft. A woman tried to solve the problem by phone. Finally, she gave me the address of a Microsoft Solution Provider. The MSP was the person who recommended the Zorin OS. He said that it is much faster than Windows, it is virus immune, and ease to install. However, I would like to have a Windows solution, since many people who deal with us still use Windows.

If you want that everything is fast again do a clean Windows Installation this is the best solution

Work through these troubleshooting steps