YOURS PC SPEAKS WHEN YOU LOG-ON,,

open notepad paste the bellow code in notepad

dim speaks, speech
speaks="welcome back, username"
set speech=createobject
("sapi.spvoice")
speech.speak speaks

replace username with your name click save as and save as type welcome.vbs
copy file welcome.vbs and paste it in bellow address

windows-7 
c:\users\username\appdata\roaming
\microsoft\windows\start menu
\programs\startup

windows-xp 
c:\documents and settings\all users
\start menu\programs\startup

*replace username with your username and c:\ with your root drive
done
log off and log in.
Now your
computer welcomes you.