Solution: This means the font file is corrupted. Delete it from C:\Windows\Fonts and reinstall a fresh copy of the exclusive version.
This is the trickiest part. Bijoy 71 was made for Windows XP/7. Installing the font is easy; getting it to type is hard. Follow these steps precisely:
Step 1: Register the Font
Step 2: The Registry Hack (Crucial)
Step 3: Install the Keyboard Layout (If available)
Step 4: Usage in Software
Some tech archives offer the original Bijoy 71 Ekushey version as freeware because it is considered abandonware (software no longer sold by the original publisher). However, proceed with caution: