i want to knw..hw we can assign particular privileges for particular account..i knw hw to give administrative privileges to a user acoount..

To create a new group open Computer Management, (Start - Control Panel - Administrative Tools - Computer Management). In the console tree, click Groups. Click Action, and then click New Group.
In Group name, type a name for the new group.
In Description, type a description of the new group.
Click Create, and then click Close. To add users to the group, click the add button.

To specify custom rights for the group, open Administrative Tools (from control panel), and then open Local Security Policy.
Under Security Settings , open Local Policies , and then open User Rights Assignment. Double-click the user right you want to change, in this case it would be load and unload device drivers. Click Add user or group. Go to the Object types box and check that groups is ticked, click OK. Then click the accounts or group to which you want to assign the right. Click OK, and then click OK again to get back out to the desktop.

So this did not answer the question? You first need to create a group, then assign the user you want to that group, then using the local policies page, assign the privilege to the group.

oh.i am realy thanks full to get this answer.Its better that i got the correct answer which i am expecting.Really i am very much thanksfull for this answer.