Generally speaking, most of the programs designed for the 32-bit version of Windows should work on the 64-bit version. What`s not going to work ? Probably there are some exceptions such as several antivirus software. Let`s take a short look at a computer running Windows 7 - 64-bit version and let`s see what he`s doing with programs made for 32-bit. Take a look at this picture :
As you can see, my Windows 7 ( 64-bit ) was smart enough to create a new folder other than the one named ``Program Files``. He automatically created a new folder named ``Program Files(X86)`` and he installed them on that folder. All applications works great. Unfortunately some application might not work although it didn`t happened to me yet.
I am not talking about exceptions such as an antivirus software simply because they must offer you a 64-bit version but if an old program doesn`t work, the solution could be a virtual machine such as as VMware Workstation.
What about device drivers ?
That`s a different story simply because a driver that was created ( designed ) for the 32-bit version of your Windows probably it`s not going to work on a 64-bit version. For example, if you need a printer driver your best bet would be on the Internet. First time, identify the manufacturer and visit his website. Most of them are releasing updates so you should find one. If you can`t find it there it`s quite ugly as you`ll have to find the driver on another source and this means to use a third party website such as ``Driver Detective`` and if you find a driver at them, they will ask you to pay in order to download that driver.
Running 64-bit programs on a 32-bit computer
If the software was created only for the 64-bit version it won`t work on a 32-bit version. Again, you`ll have to repeat those previously steps and I mean to go at the manufacturer website and see if a driver it`s available.
Usually, all programs and devices that will work with Windows 7 should display a logo called ````Compatible with Windows 7``. Theoretically, such programs were tested and they should be compatible with both versions: 32-bit and 64-bit versions.
You can perform an additional check by visiting the ``Windows 7 Compatibility Center`` and see if there are any information regarding the program that you`re interested. According to Microsoft this is a permanently updated list.
What about device drivers for 64-bit ?
If we`re talking about hardware devices, again, it`s a different story as all of them requires 64-bit drivers to work on a 64-bit version. If you try to install a 32-bit version of Windows on a 64-bit version it`s not going to work.
You`ll have to visit the device manufacturer`s website and let`s hope that they released the desired version. Additionaly, try to search on the Internet for people with the same problem, perhaps someone else already found a solution.