Help - ppsspp doesnt load (only black screen)

[Simona]

I have a problem. I have installed the ppsspp successfully and it was working just fine but after i switched my computer off and on, it wasn´t working at all. When i try to start it, its black (i mean no menu, no game load and so on...). I have tried to reinstall it but that didnt seem to help. I cheack if ma computer was good enough and it is. Only promblem is windows vista but still it worked just fine yesterday.
If someone could help me, i would be really glad.
Thank for your help.