Thanks to community, my problem solved when I updated Bios of my machine to 1.18 (from Acer official Website).
I am little new to Ubuntu and Linux. I was using Ubuntu excellently in my old laptop Acer Aspire 5920. Recently I installed Ubuntu 10.04 in my new Acer Aspire 4745 and I am very much disappointed since it could not configure correctly. one of the problems is my battery applet is missing at right corner of top panel, I tried by 'add to panel' by right clicking it but no use, and I also tried from Power Preference, when change the settings 'display always' it displays but doesn't response to battery changes.
As far as I thing it is some system configuration problem, Ubuntu could not detect the battery as it seems to me.
Another problem is I could not record sound using Gnome-Sound-Recorder.
Please give me some solution since I am new and don't have much software knowledge.