My panels seems windows

[guerrero obscuro]

I tried to install open arena in my xubuntu, (pentium 4 250 mbram 64mb video intel) all dependencies look well but when i start the program my pc just keep in black. so i reboot but my panels had the aspect of windows what can i do?
sory my english.

http://lh5.ggpht.com/_tIPxjvayAdg/TLdv0OxtvhI/AAAAAAAAAhY/ZAxqf4DTXmw/s640/Captura%20de%20pantalla.png