Hi, any advice much appreciated: My MacBook has just started to cut out when not plugged into the mains. It doesn't seem likely to me that this is a problem with the battery itself, as it was performing fine a few days ago, lasting several hours with no problems. Now, if I unplug the mains charger, it cuts out straight away, and if I try to switch it on when unplugged, it makes a feable noise as if trying to start, but to no avail. Has anyone else had this problem? Perhaps it could be a problem with the battery contacts - the connection between the battery and the power supply? I'm not getting any error messages, and the battery meter shows as 'fully charged' when plugged into mains. Many thanks.