Philips dvd+rw dvd8801 will not read or write dvds

just over the past few days i have been doing some burning of dvds and have no problem untill last night i guess you would say the problem would be i can place the dvd in the drive and close it but as soon as i close it it opens back up and for the love of me i cant figguer it out ( plus to say im not very computer friendly ) what could the problem be??? ( it will read cds ) anything will be helpful