hi to all....

i want to know how does a computer work after it is switched on, which device gets the power thru smps is it ram, could someone tell me in detail regading this...

first thing first!
SMPS
Switched-mode power supply - Wikipedia, the free encyclopedia

Note that the power is not turned off when the computer turns off. There are electrical components on the motherboard that has a constant charge of electrical current going through them....as long as the power cord is plugged in.

When the off/on switch is thrown power is supplied to the the BIOS chip first and then is sent out to power up the various components for identification purposes only...this includes the processing chip. Once the BIOS identifies everything it signals the boot proceedure and then the CPU to take command.

Really quite simple

thankx that was really informative ...... does that mean power first goes to bios chip and then to RAM??

RAM = Random Access Memory

exactly right as ram must first be verified by the BIOS and is not needed. The only memory that is required during the start-up is really the
EEPROM which stands for Electrically Erasable Programmable Read-Only Memory, is a type memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed. This is what is refered to as CMOS ( which is really different things all together) and an onboard battery is utilized to provide constant power to avaoid loss of data stored.