HI! I replaced kdl 32l5000 ir board but remote still does not work. Do I have to perform any type of steps after doing such replacement?

It is plug and play. Are you getting 5 or 12vdc feeding the IR PCB assembly?
You need a scope to look for output pulses coming out of the IR board when it receiving the signal from the remote controller.

1) Test the remote:
The remote control puts out IR (InfraRed) signal that human eyes cannot see, to find out if the remote is sending out the signal or not you just point the remote at the digital camera's Lens (Digital Camera can detect IR), you should see flashing light on the camera's screen when any one of the remote button is pushed. If you do see the flashing on the camera, then the problem is in the TV IR receiver or the main logic board; more troubleshooting with scope will be needed to look at the signals.
Parts: www.shopjimmy.com

2) If the remote checked out OK, then look at the back of the TV for the "REMOTE INPUT", use a mini-phone plug and insert the plug ino the remote input jack in and out a couple times to clean the switch contacts that select between the front IR receiver of the TV or the rear panel IR input jacks.

http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague