My dell inspiron 1520 says no battery detected . and i also noticed that the fan is not working.the problem happened just 4 days ago.when my laptop was totally dischharged 2 times in a row.Then first it didnt charge more than 40%.then increases a little bit to 43%.and today when i was using it on battery power and it showed warning that 11 min left i shut it down .when i restarted with AC power critical battery charge led was blinking and showing only 29% charged and charging. but the charge remained 29%.and now it is showing no battery detected.if i disconnect the AC charger the laptop immediately turns off. My laptop is abt 18 months old but never gave any problem before. i opened the battery and again reattached it .but nothing changed.my warranty was 1 year. . can someone tell me what to do?? edit: i have noticed that bios is loading very slowly sometimes at startup now.