here is my problem I recently installed windows seven and also bought a 9 cell battery for longer use time on laptop
when I installed the battery after update to windows seven battery says plugged in not charging
I have updated the bios from the acer website and it was an executable file so easy to do and all went well but still have battery not charging
when i install the old 3 cell battery it charges fine
other problem i have encountered is since windows seven install I used to have dual display but now only have single also task manager shows 2 cpu's which is quite stupid since this is a single cpu have tried to update all drivers from acer website for this machine and although some did conflict at firstand after reinstall they were fine it has not sorted the problems I now have with this machine although it runs extremely well as for speed and stability its never been better just would like for new battery to charge
Windows 7 will show 2 processors in device manager if you have a 2 core processor or a processor with hyperthreading - in your case you have hyperthreading.
Was the 9 cell battery charging on your old OS or have you only tried it with windows 7? Is it a branded Acer battery or a 3rd party unit? Also, although windows 7 states the battery isnt charging is the battery itself actually holding a charge?
With your dual display problem it sounds like you may have a driver issue? Are you using the display drivers that windows 7 installs or have you installed the official Acer drivers?