Activating 64bit using 32Bit Key

My Laptop Compaq CQ61 Shipped with Windows 7 Home premium 32bit Version. lately i upgrade it's memory to 4GB. to utilize all the 4GB memory i need windows 7 64bit OS so is it possible to use my OEM product key (that came with the laptop) for 32bit Home premium to activate 64bit windows 7? :sarc:

Yes, under the EULA you are entitled to either 32 or 64 bit with each license.