Version numbers of most applications, including PAF, are found in the applications' Help-About menu on the toolbar.
It may be better to avoid making new installations of PAF until you give things a day or two to settle down, but if you wish to re-install just do a Windows Explorer search for "paf" on "My computer" or the "C drive" if it is the only hard drive you have.
The results of that search should be a long list that may include temporary Internet files from this forum, as well as the program files of PAF 5.1.12 and Paf 5.2.18 that you have downloaded from FamilySearch.com
If you do reinstall, it would probably be better to let PAF select its own default directories (folders), unless you are certain of the changes you wish to make.
For the record, it is pleasing to see that the latest version of PAF correctly exports image linking in the RTF Print to File Book reports.