My mid 2010 MBP suffered from a swollen battery, spotted by the trackpad lifting up. Replacement battery ordered from here and I followed the clear and easy instructions on this site. At first the computer said that the battery wasn't recharging. The fix was to reset the SMC. For removable battery MBPs like mine you power down, remove the battery, press the power button for five seconds and reinstall the battery. Hey presto, it is now charging the replacement battery! Great service, great guides and thanks to all the folks who leave additional tips here.