Hi can anyone help. I have an Advent laptop (9117 I think). Everything was working fine until I tied to plug a USB device into it which caused laptop to power down. I restarted laptop and tried again to plug in USB device and again laptop powered down and will not restart. Power light is not coming on when charger connected (although power is getting through charger okay). Any assistance would be much appreciated before I take to pc repair shop (or throw laptop out of window).