You tacked onto a two-year old thread. The causes and suggestions there may not apply to your issue.
What version is being used? Explain more precisely what you are attempting. If it's dragging clips, and they are snapping back, hold down <alt> while dragging.
As for licenses, updates are free for six-months from purchase date. There's no mandate to update; if what you bought is working well stick with it - or with any release within the six-month period. Here's the download site.
Newer releases can always be test driven and most features will be available for a trial period. Or use the free version, which has some limitations from the outset.
If you make the effort to work with helpers here, problems can usually be fixed. Sometimes, they are caused by unfamiliarity, at others by hardware conflicts (not every PC in the world will run every program perfectly) and yes, by bugs. When a bug is confirmed it is quickly fixed.
Submit your project files here and we'll run the project. The process is easy, quick and can be done privately. Just follow these steps...
Back up --- With your project on the timeline, click on MENU at the top-left. Click FILE|BACK UP PROJECT FILES TO FOLDER. Choose a folder and SELECT FOLDER.
Upload --- Use a free server - Google Drive, MS OneDrive, etc.* - to upload the saved, numbered FOLDER. Do NOT upload the individual VPJ or export file.
Get link --- Get a public link. If using Google Drive click GET SHAREABLE LINK. If necessary change "restricted" to "anyone with the link can view"
Share --- Click COPY LINK | DONE. Paste that link here, or click the folder at the top-right of this forum to message it privately to me. It won't be shared.
* Before uploading, right-click the folder, click PROPERTIES. Look at the File Size to confirm that it's not too big for the free space on the server.