Google Chrome version 45 was the first build released that removed support for the Netscape Plugin API (off which Flash interfaces with Chrome), which would make the last supported build 44.0.2403.157. It is available on FileHippo.
Per some official documentation for Chromium (Google Chrome's open-source base):
To turn off auto-updates of Google Chrome on Windows, you need to instruct Google Update to not update it. To do this, you can either:
- Use the Google Update ADM templates provided on this page or as described in this article.
- Set the value of HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Update\AutoUpdateCheckPeriodMinutes to the REG_DWORD value of "0".
Here's a sample reg file source for the latter option:
Windows Registry Editor Version 5.00
All this in mind, I would reconsider what you are really trying to accomplish. This build is at least 2 months old (excluding you from future developments) and leaves you open to security vulnerabilities in Flash. I would advise utilizing this only for when Flash is really necessary, and keep your other everyday browsing elsewhere.