I have a gateway pent. 4. One day my computer was working fine, then all of a sudden it will not power up again. I opened up the computer case, clean the dust. Unplugg and replug the wires. Yesterday it stayed on for probably 2o minutes and then shut off. Today, it won't even come up. The power button is yellow, but the power light from the fan is green. Any ideas on what the cause may be? Any help would be wonderful. Thank you in advance.