Bikash,

If you re referring to Vista's User Access Control (UAC) then it is there
for your protection.  Whilst it can be disabled via the Security Centre  I
would very strongly urge you not to do so as doing this can not only cause
problems when installing some applications but also, far more importantly,
make it far easier for unwanted malicious programs and malware to install
themselves on your PC.

By the way, as I am sure you have now realised, this newsgroup is
primarily for those running the older Windows Millennium operating system
rather than Vista.