i am doing a project on remote computer access.. i want to turn on my pc remotely .. i am planning to use a gsm switch will supply power to the device as soon as i send an sms .. so i want to know whether there is any way to start the cpu as soon as the power is supplied
Yes you can do that, but only as long as the said remote PC is in "sleeping"/"waiting" mode or "hibernation" mode.
Obviously, you can't do that if your PC was turned off by hard-switching, or was unplugged from it's power source. Also, your monitor should be in "stand-by" (yellow light) mode too.
Of course, first of all you'll need to know how to access your remote hardware to begin with, through net or by any other means.
I'm not sure how you would do it with SMS but you can boot up a PC that is completely off. Just google "wake on LAN".
This allows PC's that have been completely shut down to boot up by a signal sent to the ethernet port of the PC. This only works for PC's connected with an ethernet cable (not wireless). If you PC is on a router (like min is). Then you have to set up a static IP address for your PC on your router.
Once I did this, I was able to use my cell phone (you can down load a wake on PC app or just go to the web on your phone) to send the signal to my PC and it would start up. The only problem I found is that the my router dumps all of my devices' IP addresses if they have not been connected to it for over half an hour. So I'm not sure if new routers do the same thing.