Adobe Fireworks CS6 Transparency checkerboard

You say you've reinstalled Fw... have you tried a clean install using the CC Cleaner Tool ?

Creative Cloud Cleaner Tool

https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html

Could you please tell us if the checkerboard representing transparency no longer appears, or if you simply haven't set it?

1 - To set it :

1-a - either when creating the document, you choose a transparent fill

1-b - or once the document is created, you can change it from the property panel, background color and choose transparency color

2 - If the transparency checkerboard is still not displayed, try rebuilding the preferences..

To do this, you need to explore the

C:\Users\YOUR_USER_SESSION_NAME\AppData\Roaming\Adobe\Fireworks CS6\English 

(or replace english with your language folder)

You'll find two files :

• Fireworks CS6 Preferences.txt, which is the preferences file
• Fireworks CS6 Panel Prefs.xml, which is the default reference for preferences when rebuilding them.

So,

1. quit Fw,
2. simply rename the TXT file
3. and restart FW...
4. a new pref's file should appear.... 

Does the problem persist?