My Sony Ericsson z550i connect my system it says windows does not recognized it. what can i do this problem . i using windows 7 OS

SOURCE: Usb cable driver sony ericsson z550i windows xp

Dear Oscareddy

Please find the signed usb drivers here (for Z550)

http://ma3.extranet.sonyericsson.com/drivers/

Regards

SOURCE: Sony Ericsson Z550i Bluetooth

change blue tooth ic

SOURCE: folder lock for sony ericsson z550i

 this is your solution nirma. 
http://gallery.mobile9.com/f/23259/

SOURCE: Sony Ericsson W580i USB Driver for Windows 7

Try this.....
Sony Ericsson - Update Service - Update service software
Follow the instructions to install the USB Flash driver. ... W580i. W200i. K550i. W800i. K508i. K790i. K530i. W960i. P910i. K700i. W550i. Z520i. M600i. W660i ...
sonyericsson.com/cws/support/updateser...

hope it will fix the issue so dont forget to rate it...

Steve Brown

• 688 Answers
• Posted on May 28, 2009

SOURCE: MASTER RESET CODES FOR SONY ERICSSON

Here are the Master Reset codes for your phone.

Master Reset / Codes
Accessing the Service Menu - Move joystick right, press * key, move joystick left twice, press * key, move joystick left, press * key.
Checking Firmware Version - Move joystick right, press * key, move joystick left twice, press * key, move joystick left, press * key, press 1 key twice.
Show IMEI # - press * key, press # key, press 0 key, press 6 key, press # key
Manual brightness adjustment - While in camera mode, press and hold * key and move joystick to lower brightness, press and hold 0 key and move joystick to increase brightness
Quick ScreenSaver - Pressing # and * at the same time
Show screensaver and lock keypad - press * and lock keys
*#0000# - Reset language back to english
Hard Reset -Hold power for 10 seconds