It is not recommended.. anyway, yes, you can.
What you want to turn off is probably the User Access Contrl (UAC).
Go to the Control Panel, User Accounts: there you'll have a link saying "Turn User Account Control on or off".
Confirm the UAC prompt once again, then clear the checkbox so your system will not use UAC.
You'll have to restart your computer then.
After the reboot you will not be prompted for every administrative task...