32bit-64bit

Yes, but how much it's going to cost you depends on your setup.

If you purchased a prebuilt computer (Dell, HP, eMachines, etc.) with an OEM license of Windows Vista, then you'll have to purchase a new license along with a 64bit disc. If that is the case, I recommend you get Windows 7. An upgrade disc will do, they run about $100.

If you have a retail version of Windows Vista (that includes the upgrade version), then you can go to this website:

http://www.microsoft.com/windowsvista/1033/ordermedia/default.mspx

and Microsoft will send you a 64bit version of Vista for a small fee (~$10).

In any case, you will have to perform a clean install to make the move from 32bit to 64bit.
 
To switch from 32 bit to 64 bit OS requires a full reinstall of the windows system - you can not do an upgrade or conversion from one to the other. So you would need to backup all of your programs and personal files - reformat the HDD and then install the 64 bit OS - then reinstall all of your programs and personal files. (also you will need 64 bit versions of the drivers for your hardware - most can be found nowadays but some older hardware is not supported so check to ensure your hardware has 64 bit drivers available before starting.)
 

Well I know all of that my own pc is a custom built with win 7 was just asking for my friend cause we are trying to problem solve why we cannot install win7, his win vista is showing that it doesnt have a key in when it is an emachines disc that doesnt require a key, that is what is making it un-upgradable but I am not sure how to fix it.