Hello Rosario,
On the affected workstations,you can navigate to C:\Program Files (x86)\SAP\SapSetup\Setup\
and double-click on nwsapsetup.exe.
This will give you a list of preinstalled components.
Do not click install or else you could remove the components.
This error does not seem like a SapGui issue though, I would recommend the IT personnel update the .NET repositories from Microsoft.
Jude