I have an Aspire 5551-4200 that's 15 months old. The battery will only charge to 60%. I was told that the battery is probably bad and I need to purchase a new one. Any suggestions before I go buy a new battery? Status says it's "plugged in, charging." I've completely drained. I have not recalibrated (afraid that will mess it up more). System says battery is a-ok.