|Yes. It might be the powersupply. It might also be a lot of other things but you have to start troubleshooting somewhere.|
Is this a laptop or desktop system? Is it a namebrand system or custombuilt?
What are the system specifications. So far all we know is it has a yellow light and you might be running XP.
"i already unplugged everything and then plugged it back in "
I presume you are talking about external cables rather than internal cables / components.
Goin' Fishin' (Some day)