2013-07-01, 00:43 (This post was last modified: 2013-07-01, 00:50 by Milhouse.)
That leaves your router as the possible culprit, and did you try a different ethernet cable? Also, make sure you don't also have a WiFi dongle installed, even if you're not using it.
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.