1.the main deference windows 32 bit and 64 bit..
The terms 32-bit and 64-bit refer to the way a computer's processor (also called a CPU), handles information. The 64-bit version of Windows handles large amounts of random access memory (RAM) more effectively than a 32-bit system.
2.how can i run 32 bit programmers on 64 bit computer or how can i run 32 bit programmers on 64 bit computer....
Most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows. Notable exceptions are many antivirus programs.
Device drivers designed for the 32-bit version of Windows don't work on computers running a 64-bit version of Windows. If you're trying to install a printer or other device that only has 32-bit drivers available, it won't work correctly on a 64-bit version of Windows. To learn how to check for drivers, see Update a driver for hardware that isn't working properly or go to the device manufacturer's website. You can also get information about drivers by going to the Windows 7 Upgrade Advisor webpage.
3.if u want to run 64 bit OS ,mainly u remain...
support your motherboard,
CPU
4GB ram...

The terms 32-bit and 64-bit refer to the way a computer's processor (also called a CPU), handles information. The 64-bit version of Windows handles large amounts of random access memory (RAM) more effectively than a 32-bit system.
2.how can i run 32 bit programmers on 64 bit computer or how can i run 32 bit programmers on 64 bit computer....

Most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows. Notable exceptions are many antivirus programs.
Device drivers designed for the 32-bit version of Windows don't work on computers running a 64-bit version of Windows. If you're trying to install a printer or other device that only has 32-bit drivers available, it won't work correctly on a 64-bit version of Windows. To learn how to check for drivers, see Update a driver for hardware that isn't working properly or go to the device manufacturer's website. You can also get information about drivers by going to the Windows 7 Upgrade Advisor webpage.
3.if u want to run 64 bit OS ,mainly u remain...
support your motherboard,
CPU
4GB ram...