You can install 7.2 without reinstalling the lot, but it's not simple. There is a post in this forum explaining. Please hold on while I look for it.
Follow instructions here:
Bear in mind that these instructions are for an older version, but the principle is the same. Just don't mix up the x32 and x64 versions, and make a back-up of the existing 8bi files (rename to something like Camera Raw.8bi.7-3).
Yammer P wrote:
Similar instructions for reverting to 7.2 from 7.3 may be found in post #34 and posts 69+71 in this thread ("Thumbnails continually rebuilding" Bridge forum):