Sayef Azad Sakin

Boot from the ubuntu Live CD.
Open the terminal from applications -> Accessories -> Terminal.
Then find the partition of your Ubuntu OS from the list generated with the command,
- sudo fdisk -l
If your ubuntu(linux) partion is sda6,
- sudo mkdir /media/sda6
- sudo mount /dev/sda6 /media/sda6
After that you have to reinstall the GRUB
- sudo grub-install --root-directory=/media/sda5 /dev/sda
If everything went alright you should be able to reach the GRUB boot menu when you restart the computer. You can find more information from here.

Some secret code of Mobile

*#92702689# -> Warranty settings.

*#7760# -> Production serial no.

*#bta0# -> MAC address of bluetooth.

*#9999# -> Firmware version.

*#2640# -> Security code.

*#7328748263373738# -> Default security code.

*#43# -> Call waiting status.

*#2820# -> Bluetooth info.

*#7370# -> Format mobile memory.

*#delset# -> reset GPRS & E-mail Setting.

*#06# : for checking the IMEI (International Mobile Equipment Identity).

*#7780# : reset to factory settings.

*#67705646# : This will clear the LCD display(operator logo).

*#0000# : To view software version.

*#2820# : Bluetooth device address.

*#746025625# : Sim clock allowed status.

*#62209526# : Display the MAC address of the WLAN adapter.

#pw+1234567890+1# : Shows if sim have restrictions.

*#92702689# : takes you to a secret menu .

*#3370# – Enhanced Full Rate Codec .

*#3370* – (EFR) deactivation.

*#4720# – Half Rate Codec activation.

*#4720* – Half Rate Codec deactivation. The phone will automatically restart

Only for NOKIA:

*#7780# -> Factory Restore.

*#3283# -> View set creation date.

*#746025625# -> Close the SIM timer.

*#67705646# -> Remove the operator logo.

*#73# -> Reset phone timer and game.

*#0000# -> Firmware version.

*#06# -> IMEI

Get own mobile number:
*Grameenphone: *111*8*2#
*Robi: *140*2*4# or call 1200 & press 4
*Banglalink: *511#
*Airtel: *121*6*3#