I can`t do uninstalling the agent of the computer

If it's Windows, I would suggest following:
https://community.sophos.com/kb/en-us/124377

Regards,

Jak

Hi Jak, 

I followed your suggestion and I didn't find the location in the registry editor. In the next link I share you the screenshots taken of the registry editor

https://itsssas-my.sharepoint.com/personal/jartel_itsupport_com_co/_layouts/15/guestaccess.aspx?docid=1c043494748784314abe6005a568113e3&authkey=Aat4Q62a1_LT1MTRMkQLM7A

i'll wait for your help

Regards, 

Have you tried this article:

https://community.sophos.com/kb/62212

it links to 

https://support.microsoft.com/help/315346/error-windows-installer-service-could-not-be-accessed-occurs-when-you-try-to-add-or-remove-a-program-in-windows-xp-or-windows-server-2003

Other related article:

https://support.microsoft.com/help/2642495/-the-windows-installer-service-could-not-be-accessed-error-when-you-try-to-install-a-program-in-windows-7-or-windows-vista

Also related if a bit dated:

https://support.microsoft.com/help/324516/-the-windows-installer-service-could-not-be-accessed-error-message-when-you-try-to-install-office

Regards,

Jak

Have you tried this article:

https://community.sophos.com/kb/62212

it links to 

https://support.microsoft.com/help/315346/error-windows-installer-service-could-not-be-accessed-occurs-when-you-try-to-add-or-remove-a-program-in-windows-xp-or-windows-server-2003

Other related article:

https://support.microsoft.com/help/2642495/-the-windows-installer-service-could-not-be-accessed-error-when-you-try-to-install-a-program-in-windows-7-or-windows-vista

Also related if a bit dated:

https://support.microsoft.com/help/324516/-the-windows-installer-service-could-not-be-accessed-error-message-when-you-try-to-install-office

Regards,

Jak