I have tried both and still the same problem occurs, also a game boosting program I use to play other games doesn't make any difference :c
My laptop has around 3 years and i don't think it's the issue since my friend with 5 y/o laptop (vista) can play Dangan Ronpa but on JPCSP (which doesn't work for me because it cannot find java). I've read through that one long topic about Dangan Ronpa problems on ppsspp forum. I've found other people with the same problem but no solution (they have been ingnored by other people in the thread lol).
Anyway thanks for help!