There may be a file that can be edited. I don't have the Adventure Shop version. I do have the GOG version which may be similar, but I'll have to download it to check for a likely-looking file.
I'm guessing the Adventure Shop version of the game got rid of the dialog box because they thought any newer computer would not have a problem with the 3D acceleration. However "turbocache" is not real graphics memory (it's "shared" system memory -- or mostly "shared" system memory) and it's possible that could cause a problem.
+_+_+_+_+_+_+_+_+_+_+_+_+_+_+_+
OK. I've installed the GOG version of the game.
It displayed a box the first time I started it.
Interestingly enough, the 3D box was unchecked by default.
Look in the folder where your TLJ is installed.
There should be a file called preferences.ini
This is the contents of my game's preferences.ini file:
; Preference file for The Longest Journey
[Preferences]
bool_AprilHighRes=1
SfxVolume=1.000000
VoiceVolume=1.000000
MusicVolume=1.000000
bool_Subtitles=0
bool_ShadowsOn=1
bool_DisableWarnings=1
bool_SkipCD=1
bool_HighResVideo=1
bool_AllowFastForward=0
bool_UseGFX=1
bool_IsFirstTime=1
[DirectX]
GfxDriver=display
int_BitDepth=32
bool_IsDoubleBuffer=1
bool_UseHardware=0
bool_StartFullscreen=1
bool_ForceSingleBuffer=0
[SoundSection]
DecompressedBlockSize=16384 ; length of datablock that should be decompressed in mixingloop
WorstcaseFrameRate=10 ; how often should the mixing occur
StreamBlockSize = 4096 ; length of the block of data loaded by streams
BlockSupplyLength=32 ; number of blocks a stream should have loaded in advance
I'm guessing the line that says
bool_UseHardware=0
is the line that tells the game not to use 3D acceleration.
The line that says
bool_IsFirstTime=1
may be the one that tells the game to show the 3D box, but I'm not sure.
To edit the preferences.ini file, right-click it and choose Edit from the context menu.
If you see
bool_UseHardware=1
change it to
bool_UseHardware=0
and save changes to the file.
If you see a line saying
bool_IsFirstTime=0
then changing it from 0 to 1 may make the box with the 3D option appear when you start the game. If you want to see the configuration window, you can try making the change and saving the file.
If the preferences.ini file is "read-only," you'll have to change that before saving changes to the file. To do that, right-click the file, choose Properties, and untick the Read-Only attribute on the General tab and OK it.