Battery drained very quickly, and OS question

[pennsword]

I got my Bold 9000 several weeks ago. For the first week, the battery lasts the whole day, I just need to charge it overnight and it's ready for the next day.

I don't know when precisely, but after I tried to install new OS, my battery drain very quickly. Researched online and tried to follow the basic suggestions.
Turned off 3G, turned off GPS, never use Bluetooth, turned off wifi. Only apps running in background (alt-esc) are Phone, browser, message and BBM.
Yet my battery will go in 5-6 hours even without real use. Bought new battery and it still the same.

Last time I put in new battery before I sleep at around 12, turned the mobile off (using the turn off icon inside the menu), when I woke up around 9-ish, only 65% left.

Tried several hybrid with no success, still has the same issue.

My question also related to the Blackberry itself. I bought mine second, I think it used to be Entel Pcs mobile as it always display that even after I installed different OS. Everytime it's new, I got message welcoming me to Entel Pcs when I reinstall new OS eventhough I'm using my mobile in China.
I always wipe first, uninstall all OS on PC before installing new OS. But when I tried to downgrade, I got a message whether I want to install older OS or leave it be (even when the blackberry has been wiped)
Is that normal?

[delfteo]

What OS do you use now.
Happy new year.

Enjoy DelftEo

[dbxd]

I get the same problem with my Blackberry Tour 9630, battery issues and stuff. I wish there was a fix.

[pennsword]

Happy New Year
Now I used 4.6.0.266

I used your OS actually, but the battery drain was still there. Also OS5 based browsers doesn't have the monternet option, and I am using GPRS mostly for internet here.