Ola jonypedrosa e bem vindo ao forum.
Olhei no site da Microsoft e achei isso:
"
Steps to take before installing Windows 7 Service Pack 1
How to increase your chances of installing Service Pack 1 successfully.
http://www.pagestart.com/win7sp1steps021611.html
(Revised 2/24/11 - 5 new steps added to help insure success) some of which are listed below.
Update your device drivers to the most recent Windows 7 device drivers from your
computer manufacture's support web site (for your specific make and model)
Start by installing the chipset/motherboard driver follwed by the remaining available drivers.
Run the SFC /SCANNOW command. This will check and repair if necessary any critical Windows system files.
Click on Start/All programs/Accessories then
Right click on Command Prompt option and select 'Run as administrator'.
At the command prompt enter: SFC /SCANNOW
Run the System Update Readiness Tool:
http://support.microsoft.com/kb/947821/en-us
Try Renamng the 'Software Distribution folder': (This could be the cause)
http://www.pagestart.com/win7sp1steps021611.html (Step #10)
Also: Steps to take before installing Win7 SP1
http://support.microsoft.com/kb/2505743
Free unlimited installation and compatibility support is available
for issues related to Windows 7 Service Packs:
Note: Availability of chat, phone or e-mail support differs depending on your geographic location.
Some issues may require more advanced support for which there may be a charge: https://support.microsoft.com/oas/default.aspx?&gprid=14496&&st=1&wfxredirect=1&sd=gn
Windows 7 - Service Pack 1 – How to install Step by Step
http://www.pagestart.com/win7sp1sbs02201101.html
Learn how to install Win 7 SP1
http://windows.microsoft.com/en-US/windows7/learn-how-to-install-windows-7-service-pack-1-sp1
Win7 SP1: Installation tips
http://windowsteamblog.com/windows/b/bloggingwindows/archive/2011/02/16/windows-7-sp1-follow-up.aspx
Troubleshoot problems installing a service pack for Windows 7
http://windows.microsoft.com/troubleshootwindows7sp1
Tambem ha outra discussao sobre esse mesmo topico aqui:
http://forums.techarena.in/operating-systems/1395063.htm
Espero que ajudem!
Cumprimentos
