open registry editor
find
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
in d right side u will find d value NoDrives
double click on it 2 change its value corresponding 2 drive letter u wan 2 hide
4 eg if u wan 2 hide drice c: and f: den from d list given below find d number corresponding 2 c & f
it is 4 & 32 add them it is 36
doubleclick on NoDrives in d white space u c type in d value
press F5 and ur drive shud dissappear
the decimel numbers corresponding 2 each drive
A: 1, B: 2, C: 4, D: 8, E: 16, F: 32, G: 64, H: 128, I: 256, J: 512, K: 1024, L: 2048, M: 4096, N: 8192, O: 16384, P: 32768, Q: 65536, R: 131072, S: 262144, T: 524288, U: 1048576, V: 2097152, W: 4194304, X: 8388608, Y: 16777216, Z: 33554432, ALL: 67108863