A lot of newer PC's sold today come with a 64-bit processor - this means that it can handle more memory and run tasks faster.  Normally your PC will also come with a 64-bit version of Windows

 

When downloading software/drivers etc off the internet you need to know what version of windows your computer is running, i.e. 32 bit or 64 bit, as most downloads have separate downloads for each version and installing the wrong one can cause major problems with your installation of windows

 

To find out what version you have - Click Start, Control Panel, System and Security, System and the dialog box that is displayed will show you what version your computer is running

 

 

So if it says 32-bit then look for downloads that state 32-bit or x86, for 64-bit look for downloads that state 64-bit or x64