Help my! my computer not shut downnnnnn

[Gusty]

Hello everybody

My name is Gustavo, to Buenos Aires, Argentina.

Sorry, but my english is not good.

I have a problem.

My computer in system Mac Os X is not shut down. The system is log out, but the screen still with my wallpaper.

 

Intel Core 2 DUO 6700

Mother ASUS p5w dh deluxe

4 gb ram dual channel (4x1gb)

2 hard disks 250gb sata2 wester digital caviar 300 16mb buffer

graphic card asus gforce en7600gt 256mb ddr3

dvd rw LG

mouse and keyboard genius ps2

 

2 Systems

1 disk= Windows XP professional, service pack 4

2 disk= Mac OS X 10.4.5

 

Thanks!!!!