The battery on my Advent 6411 died and I obtained a replacement from Partmaster. The original battery had an output of 3600mAh but the battery supplied was 4000mAh. On start up error messages came up saying that the battery voltage and charger voltage was invalid but the computer booted up OK. However the power properties did not register a battery being installed, said that it was running on mains (even when unplugged) and didn't show the battery charging. After repeated phone calls to Partmaster and my computer support service I was told that this was the only battery available and that there is no way of modifying the BIOS or battery properties to have it recognised. I am now stuck with a three year old laptop which is only usable as a desktop even though I have a 5 year coverplan service cover which I am told excludes the battery. Has anybody else had this problem or know how to deal with it or where to get a 3600mAh replacement battery?