what is the difference between 32 bit and 64 bit

First of all, a bit is a binary computer information. It's 1 or 0. All the data in your computer are in binary. Using 32 bits, you can represent effectively a number from 0 to 4 294 967 296 (2 exp 32). For 64 bits, it's from 0 to 18 446 744 073 709 551 616. So your computer can use more information at the time. How does that affect the performance ? First of all, 64 bits means also that the computer talk to the memory at 64 bits, meaning that there is two times more information coming from the memory in the same time as a 32 bit computer. Also, large calculation is done very fast, since you can handle at the same time twice of the bits. But for day to day purpose, there is no much difference, because you don't use long calculations and most of the windows application are not compiled in 64 bits.

32 bit is old-style, outdated, and slow. 64 bit is the norm now. To run recently produced applications successfully, you really need a 64 bit processor. If you have a 32 bit, chances are that you're getting lots of error messages like, "Out of Memory", or "Memory Insufficient to Run Application". By upgrading to 64 bit, you will find these error messages very rarely, if ever, pop up.