Delete Gw2.exe, then rename Gw2.tmp to Gw2.exe. When Gw2.exe is updated, it downloads the new version of Gw2.exe to Gw2.tmp, then launches Gw2.tmp and finishes the update by renaming itself (Gw2.tmp) to Gw2.exe. When this last step fails, Gw2.exe is left as a 0 byte file while Gw2.tmp is ~30 MB (because it's the actual Gw2.exe). It worked!! Thank you so much.You are awesome!