about closing startup form to load application....

Question

hi, i m trying to load statup window and then after validating user i want him to mdi form. i m able to open mdi form but i m not able to close startup form. in mdi load event ... i have written code ..... frmstartup startup = new frmstartup(); startup.close(); then why it is not destroying it ???? will u please help me...... thank u.. - bhavin gajjar