This isn't a 32-bit vs 64-bit problem.
As Marian says, gamers have run this on 64-bit Windows 7 in the past.
However, Dead Reefs is from 2007, and a lot of things have changed since 2007...
* Video cards and drivers
* DirectX 9.0c (lots of different versions are called 9.0c)
* Antivirus restrictions
* Windows Update restrictions
I wasn't able to find much online about running Dead Reefs on newer versions of Windows, but there's a little at PC Gaming Wikihttps://pcgamingwiki.com/wiki/Dead_Reefs
One thing you can try is to right-click the game shortcut --> Properties --> Compatibility tab
Put checks in checkboxes for:
* Disable display scaling on high DPI settings
* Run this program as an Administrator
Save the changes and exit
See if the game works any better
You can also try changing compatibility to XP, but I've had more luck not doing that, and changing only the settings for Administrator and display scaling.
Make absolutely sure you don't have an antivirus blocking the game. Microsoft Security Essentials doesn't usually block games, but some of the others do.