Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi Glenn,
As per your description, “when i open the Application and want to sign in the screen the window were you sign is just blank, tried several times but still wacn't sign”. I understand you are unable to sign into Office 365 applications installed on your Windows 7 computer. As you are using Windows 7 OS, I should mention that support for Windows 7 ended on January 14, 2020.
Office 365 and Microsoft 365 are governed by the Modern Lifecycle Policy, which requires customers to stay current as per the servicing and system requirements for the product or service. This includes using Microsoft 365 Apps on a Windows operating system that is currently in support.
For your reference: Windows 7 end of support and Microsoft 365 Apps Microsoft Office 365 no longer supported on Windows 7. In this situation I suggest you please upgrade your Windows to windows 10 for use Office 365 better experience.
Reference: Windows 7 to Windows 10 manual upgrade step-by-step guide
Further, you may try the following suggestion, see if this help you fix the issue.
1.Clear the Windows Credentials
a. Sign out from Office application and close all the Office applications opened on your system. To sign out, open any Office application, let’s say Word, click File>Account>Sign out.
b. Open Control Panel>User Account>Credentials Manager>Windows Credentials>Delete all MicrosoftOffice16 and MicrosoftOffice15 credentials.
c. After deleting the cached password, open Word and click File>Account>Sign in and enter your Office 365 log in credentials.
- Update your internet explorer to the latest version.
If the issue persists, we strongly recommend you move to Windows 10, because your installation of Microsoft 365 Apps won't receive any new features updates if you continue using Win 7 OS.
Regarding to installing .NET framework on the PC with Win 7 you may refer this thread for solution with detailed steps and see if help for you.
I appreciate your time and understanding.
Best Regards
Waqas Muhammad