First lets check the version of Internet Explorer you have installed. Press the ALT key on your keyboard and click on the Tools menu in the menu bar of IE. Click on About Internet Explorer. If it shows that you are using Internet Explorer 11, we will need to a bit more to get this working. If it is Internet Explorer 10 or lower, you can skip this next paragraph.
For IE11 we need to set it to use Compatibility Mode when you access your site. You can follow the steps here: http://windows.microsoft.com/en-us/internet-explorer/use-compatibility-view#ie=ie-11 . After following those steps see if you can access Cube Reports now. If it does, great! If it doesn't, try the following.
We'll need to double check that Office Web Components is enabled. Head under the gear icon in the top right and choose "Manage Add-ons". In here should be an addon called "Microsoft Office PivotTable X" where X is the version number. If you do not see this, change the drop down in the middle left to show "All add-ons".
If it doesn't show up, you will need to redownload the software here: http://www.microsoft.com/en-us/download/details.aspx?id=9468
If it does show up and says Disabled under Status, click on the addon name, then click Enable at the bottom right.
If it does show up and says Enabled under Status we need to make sure it's set to run on your site. Head to your report and view it as a Cube Report. When here, Go under the gear menu ( or Tools ) to Internet Options. Click on the Security tab, then click the Trusted Sites icon. Now click on Sites and then click the "Add" button. Then "Close" and "OK" and retry the cube report.
If you get an error in a Cube Reports like window we need to double check that settings have not changed. Head under the gear menu to Internet Options. Here, click the Security tab and click the Trusted Sites icon. At the bottom is a Custom Level button. Go ahead and click on that. The window that pops up will be a long list of options. The one we're looking for is just about in the middle of the entire list. "Access data sources across domains" needs to be enabled.
If that still does not work, there is one last setting to double check. In Internet Options click on the Advanced tab. About three quarters of the way down is the Security section. In there is a checkbox titled "Do not save encrypted pages to disk". Make sure this checkbox is not checked.