Anything in the game's log/dllerror.log file?
Is the game crashing when you fire a photon weapon? Is it crashing when you're loading into the area (before you actually see Forest 1 for example)? If it's crashing when you're firing a photon weapon offscreen, it's likely a DEP crash. Check the first thing in the Technical section of the FAQ here:
https://ephinea.pioneer2.net/faq/#technical
If nothing in dllerror.log and it's not a DEP crash, try to find the Windows crash info. Open Event Viewer (open Start Menu, type Event Viewer, and Windows should show you the default System app), expand Windows Logs on the left, click on Application, wait for it to load the events, and then find the Error event for when PSOBB crashed. It'll look something like this
Code:
Exception code: 0xc0000005
Fault offset: 0x004f840e
Faulting process id: 0x167E0
Faulting application start time: 0x1DBCB733CA5E621
Faulting application path: C:\EphineaPSO\psobb.exe
Faulting module path: C:\EphineaPSO\dinput8.dll
Post only the Exception code, Fault offset, and the final component of the Faulting module path (not the full path--just whatever is after the final backslash). In my case, it would be this:
Code:
Exception code: 0xc0000005
Fault offset: 0x004f840e
dinput8.dll
If you see something like dxvk or dgvoodoo or dvnum for the fault module, it might be an issue with whatever Direct3D Renderer API you selected in the launcher's options. Try starting with Direct3D 8 and make sure you turn off anti-aliasing and anisotropic filtering.