my battery was working fine ( moderate use 1 day and a half) suddenly its barely lasting 7 hours on stand-by !and i didnt install anything new on it ! how do i fix that !? i dont want to install 100 programs in order to reflash and stuff !!

i know this sounds mental but i had a nokia n73 which did this and it turned out to be the sim card.
i had a lot of other problems which i assumed were not connected like the fact i could only recieve txts and i would lose network connection everytime i entered into the range of another cell tower and would have to restart to get connection (unless i had an active call running).
i used to wonder around with the Orange recorded information line playing in my pocket so i didnt have to restart it.

Anyway i changed the sim card to fix these probs and then my battery life jumped from about 7 or 8 hours to almost 3 days.

Don't ask me why i don't know maybe a combo of the fact that i had an active call when i was going somewhere new and maybe because it was always trying (and failing to acquire signal) but i doubt it would have mad as much difference as it did.

i'll try that..i'll go and replace the sim card ! but i noticed it drains most when its idle (stand by)... hopefully it'll fixed

have you tried rebooting the device?

I once had the same issue, so I installed Conky, and it showed that a process was stuck using 100% cpu. After a reboot everything went back to normal.

can they make a reboot harder ?!?

Write "dmesg" in terminal.. look for anyting repetitive or errors.