to enable aero(window transparancy)
right click your desktop and select personalize
click colour and apperance and check the transparancy box
in your task bar quick launch is an icon that looks like some windows in a cascade
click it to enable the 3d alt and tab option
if the transparancy and 3d mode are not working i havent a clue why
im guessing but your desktop theme is set to vista ?
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BE-unlimited 13731 / 1304 36.5db 4.4snr
vista x64 ultimate, asrock 939 dual sata 2, athlon64 x2 4600+@ 2.53ghz(x2) ,2x1GB ocz platinum cas 2,3,2,5
soundblaster X-fi ,iceq3 x1900xt 512mb,300gb sata 16mb ,120gb ata133 8mb,enermax liberty 500watt psu
antec 900 ultimate gamer case, samsung 226bw-s 22"