Street fighter 4 pc crash issues

Greetings and sorry if this discussion it’s already been posted.
A friend of mine has some crash issues with sf4 pc version.It randomly crashes in several moments (character screen on SOME characters,title screen etc).The error name is “Fatal Error : An unhandled error occurred. (-1)”.After rebooting the computer,the problem doesn’t show for a while,but it happens again after some games.He did some mods to the game (costumes,stages etc),but i don’t know if that’s the problem.His PC specs are:

OS: Windows 7 ultimate 64 bit
Processor: Intel core i3 cpu 540 3,7 ghz
Video Card: Ati Radeon hd 5670
Motherboard: ASUS p7p55d-e

Well, it could very well be the mods.

Try running the game in a vanilla state first and see if any issues show.

It’s strange because many other ppl had the same issue WITHOUT modding the game.And that would mean that the game can’t be modded?He did so many changes he would like to not lose them by reinstalling the game.