Hello
When I try to install SP5 in solidworks, stopped at a percentage of completion in the installation, the following error message is displayed: "Internal error: The Windows Installer service was not executed as expected for this component:SldToolboxUpdater" contact technical support.
If you have the solution to this problem, thank you in advance for your help.
Hello
If it's version 2015, please check if the Microsoft KB3072630 is installed from Windows Update, like this:
1. To open Windows Update, click the Start 
button . In the search box, type Update, and then, in the list of results, click Windows Update.
2. In the left pane, click View Update History.
If so, you should uninstall it by following this tutorial:
http://www.mycadblog.fr/problemes-solidworks-rencontres-apres-la-mise-a-jour-de-microsoft/
Or repair SolidWorks installation from the control panel > programs > SolidWorks > right-click repair
If it doesn't work, you can reset the SolidWorks settings (which you can restore later) to determine if it comes from the configuration of the workstation: http://www.lynkoa.com/tutos/3d/reinitialiser-les-parametres-solidworks
Using the toolbox?
You can also try to repair the SolidWorks installation from the start menu.
And it is always advisable to update your graphics card drivers through this site:
http://www.solidworks.fr/sw/support/videocardtesting.html
And disable all antivirus during installation.