Help! I am new to this board and sadly the most knowledgeable computer person in our office. Which is not saying much. I have a Dell PC I think one of the firsts pentium 4's. I has been working fine but yesterday it just wouldn't turn on. I opened it up and it was quite dusty so I cleaned it out. I plugged it into what I know to be a working outlet and with the cover off noticed a flashing light on what I believe to be the mother board. When I unplug it the light goes out so I assume the PC is getting power. Any Ideas? Thanks.