Hai
If u want to change password as ur design,just get 3 text box values,first check with current password with db and then compare new pass and confirm pass and then update in user table.
If u want to reset password,u need to get new password and user email address,check email address is correct or not with db,and update new password in db and also send new pass word via mail,bca u have user email address.
The above 2 way u can use,all are easy ,just select query ,compare values and update values,in ur project u use all queries why u need codings,just use ur exesting query and chnage little bit.
try this link
select update insert delete commands in c# asp.net[
^]
Regards
Aravind