My Acer 5742G has problem with BIOS 'coz when I power on the laptop only a black screen appears, no hdd led activity,no bios welcome message. So I'm gonna fix it by flashing BIOS. Right after this black screen problem occurs the charging was not working properly. Sometimes it was charging from the mains supply & sometimes it doesn't. I've disassembled & checked the charging socket for any short using the multimeter and there was no short in it. After that I assembled it again & it was charging from the mains supply. When I powered on, the charging LED went off and again it doesnt charge. I tried replugging the charger but no results. I've tried with different charger for this model but it doesn't gets charging. If I made it upto charging then I'll flash the BIOS & get back my laptop to a working condition.