What does Ravi mean by this:

B. Perform a clean installation following the below steps: 1) Log on to the system. 2)Make sure Antivirus and Firewall is turned off. 3) Rename/Delete the registry key (if present) HKEY_CURRENT_USER\Software\SolidWorks HKEY_LOCAL_MACHINE\SOFTWARE\SolidWorks (run registry editor from Start > Run > type "regedit" (without quotes) and select OK. This will launch registry editor). Please ensure not to modify any other registry key or folder since it can lead to malfunctioning of other applications. 4) Delete all the SolidWorks installation folders (C:\Program files\ SolidWorks Corp) and all the SolidWorks Data folder (C:\). Ensure to delete all the versions of Data folder. 5) Uninstall all .net FrameWorks (from 1 to latest in reverse order) from Programs and Features. Go to Control Panel > Programs and Features > click 'Turn Windows features on or off' > uncheck 'Microsoft .Net Framework 3.5'  and  ".NET Framework 4.6 Advanced Services". Click OK.

SolidworksEducator Student