Hello, I recently got the first two games here on GOG and wanted to try the original version since I hear people are kinda mixed on Enhanced Edition. The problem is any time I try and launch the game I get the same error without fail. I went looking into multiple guides but none have been able to help solve it.

For reference the error says:

An Assertation failed in D:\Dev\chitin\ChVideo.ccp at line number 4256
Programmer says: No valid video modes supported.

The one guide said to change Full Screen in the ini file from 1 to 0, but there's no line for Full Screen anywhere in my copy, so I'm at a bit of a loss. Any help is greatly appreciated.

If you are talking about BG1, it runs unmodded at 640 X 480.
If you system doesn't natively support that, you can make a custom resolution in your video cards control panel.

...........................................________........................
....................................,.-‘”...................``~.,..................
.............................,.-”...................................“-.,............
.........................,/...............................................”:,........
.....................,?......................................................\,.....
.................../...........................................................,}....
................./......................................................,:`^`..}....
.............../...................................................,:”........./.....
..............?.....__.........................................:`.........../.....
............./__.(.....“~-,_..............................,:`........../........
.........../(_....”~,_........“~,_....................,:`........_/...........
..........{.._$;_......”=,_.......“-,_.......,.-~-,},.~”;/....}...........
...........((.....*~_.......”=-._......“;,,./`..../”............../............
...,,,___.\`~,......“~.,....................`.....}............../.............
............(....`=-,,.......`........................(......;_,,-”...............
............/.`~,......`-...............................\....../\...................
..............\`~.*-,.....................................|,./.....\,__...........
,,_..........}.>-._\...................................|..............`=~-,....
.....`=~-,_\_......`\,.................................\........................
...................`=~-,,.\,...............................\.......................
................................`:,,...........................`\..............__..
.....................................`=-,...................,%`>--==``.......
........................................_\..........._,-%.......`\...............
...................................,

play stupid games win stupid prizes.

not the first not the last to...

I posted this link in a different thread regarding some graphics issues, but you might give it a try, since this is meant to solve issues with modern operating systems and hardware:

https://www.reddit.com/r/baldursgate/comments/lx6d1k/how_to_run_original_baldurs_gate_and_other_old_ie/

Some people disagree with some of the content changes in the Enhanced Editions. I am not aware of anyone who would make the argument that the Enhanced Editions are more difficult to make run than the Classic Edition.

Given that the Classic Edition here is not working at all for this user, running the Enhanced Edition, even if some of its changes are disagreeable, is probably the path of least frustration. Personally, having played BG:EE and BG2:EE but not BG1:CE or BG2:CE, but having read about some of what EE changed, I have no regrets about going direct to EE. Its changes do not bother me, and it did work correctly immediately after install. I did not spend any time messing around with crashes, screen layout, etc. Note that I have not bought or played Siege of Dragonspear, so I cannot comment on its content.

Not to mention that if it's the new NPCs/quests that they have issue with, there's a mod out there that will remove them and you don't even have to see the new stuff if you don't want to. There are also some people who say that backporting the new kits/spells/etc. back into BG1 makes it easier, which I think is a fair argument, but you still have the option of not using those new skills at all if you're that concerned about original purism.

I think everyone should know that there is a good source port for the classic versions: https://gemrb.org/

And for other Infinity Engine games. Maybe it be interesting to try this. :)

This actually worked, thanks a ton!