Well rohan, this doesn't work for all operating systems... A good way to check is to first press Ctrl+Shift+Esc to open task manager then click the processes tabs. If you see *32 beside some of the processes running then that means your computer is 64bit and that program running is 32 bit...note...you won;t see *32 beside system processes cuz they would have been installed for the specific type of system whether 32/64
Obviously if you dont see any *32 then all processes are 32 bit, meaning that computer is 32 bit.