Whats the difference between 32bit and 64bit OS's or applications. I understand it a little but its just not clicking the way the teacher explained to me

thanks, any info would be much appreciated

All OSes can can process 32-bit and 64-bit numbers (actually, even longer ones). And, if the hardware supports, say, 64-bit integers natively, then it is possible for a compiler to support those instructions on any OS.

But, what one usually means by a "64-bit OS" is that the OS itself exploits the newer features of a 64-bit processor. That is, if native data moves are in 64-bit chunks, then the OS moves data that way. If a huge amount of memory can be addressed, then the OS can use it. If device drivers can be faster because of higher bandwidth, then the OS has such drivers. And so on.

But, even on such an OS, whether applications use the "64-bit features" is entirely up to the design of the program and/or the compiler that's generating the code.