Does the file name change when converted?

The file name is appended with _OC<version number> after conversion.

Once the software is activated, how can I scan files without decreasing my activated file count?

Select "No Updates - Scan Only".
When clicking Scan/Convert from the Toolbar the first form that appears has the option of selecting how OfficeConverter will treat the file. At this point, select "Scan Only - Do not Save."  This assesses the file for errors before using one of the activated file quota.
Note: This scenario refers to a file limited license.