Your profile indicates you are using SketchUp version 8. Is that correct? If so, reinstalling SketchUp 8 won’t help get the 3D Warehouse to show. Upgrade to the current version.
The link to the 3D Warehouse for V2013 and earlier is no longer functional. This was effective nearly a year ago and was announced long before that. See this link for the last notice posted here.
If you are actually using SketchUp 2014 or later, it is unlikely that reinstalling SketchUp will fix the problem you have. Instead you need to look at making sure Internet Explorer is up to date and clear the caches.