Hi Normie1,
1 - To uninstall WP, simply use the add/remove or locate the correct folder in >> C:\Program Files\NCH Swift Sound.. and double click the uninstaller.
2 - To change the file association that your machine is using, click Start > Control Panel > Folder Options > File Types... and set the application you would like to open each file type.
If you continue to have issues, please respond with your specific issue and screen shots Please take screen shots for extra detail, if needed. To take a screen shot: Press the 'Print Screen' button (located next to F12 or the 'Scroll Lock' button). Open Paint (Start-> All programs-> Accessories-> Paint) and click Edit-> Paste. Save the file as a .jpeg and attach it to this reply.
Cheers
M