Ok Sorry for my language.. AC is Air Conditioner...
So this is what I did>>
1] Turned off my N900
2] Removed the battery
3] Removed the Sim Card
4] Placed the battery on n900 not inserted.. (half inserted)
5] Took the Sim to old phone and inserted in it...
After 15 minutes...
6] touched n900 to put back the sim
7] it was too hot
8] placed N900 and battery in front of Air Conditioner for 5 minutes
9] Inserted battery into N900 and connected to wall charger
10] No signal of charging for 5 minutes
11] removed the wall charger and connected to Laptop via USB
12] Got green led
13] Searched on maemo.org about battery dead and tried pressing U key while plugging usb (with and wothout battery) and tried powering on
14] some other signal other than green led
15] connected back to the wall charger got green led
16] tried [15] about 5 to 7 times
p.s.1 N900 giving steady green led (not blinking) while connected to usb or wall charger with and without battery ..
p.s.2 My N900 is new and just 1 month 10 days old.
p.s.3 battery contacts are fine

any ideas...