Background:
I am writing a Mod for the Game DungeonSiege which supports replacing game functions via "dsdlls". I am currently trying to find which function is called when a screenshot is taken during the game using OllyDbg and IDA.

Problem:
I run the game and start playing then I tell OllyDbg to attach to the exe which it does but then all of the threads except for the current one (usually ntdll) get suspended and I can't resume them. After ntdll finishes all threads are suspended and right clicking on them and selecting resume does not resume them.

Does anyone have any idea why something like this would happen? I am new to Olly and it seems like a very good program and I would like to continue using it.

have you tried running the program (F9) instead resuming threads ? also if the game has an APi i think the name of desired function it is easy to spot, something like TakeScreenshot or something like this.

if this is not possible then a dead listing (disassembling with IDA for example) is needed to seek the desired function (look for CreateFile & WriteFile)