https://www.warmane.com/download Mists of Pandaria client, when its done do the usual (stop the torrent, move the wow folder somewhere nicer and remove read only from the entire folder).
You can try some additional things if you are experiencing issues
1. In the wow.exe properties under compatibility enable Run as administrator
2. In System properties increase the size of the paging file, Advanced System Settings > Performance > Advanced > Virtual Memory
3. If the two above did not help or if you are still experiencing "Could not stream archived data" or "Could not find mpq" issues, download the enUS localization and place it in the Data folder (extracted, should look the same as the enGB folder in there), and change the config.wtf to use enUS instead of enGB. Here is the folder i use
https://drive.google.com/open?id=1fo...kSTmbz0L7U4Bt4