DVD/CD-R rom not working

okay here's the thing --

i have a compaq presario f500 (f572 to be exact) running on vista with the latest updates, amd anthalon x2, 2 GB memory. simple little machine i know, but it gets the job done for work. the problem is that i need it to burn cd's and dvd's.

it used to work just fine and now it doesnt.

when i bring up my computer the drive is showing.
when i click on properties, it shows that this device is working properly.
i have uninstalled and reinstalled -- no good
i have updated the drivers -- no good
even went and checked in the BIOS thinking it might be something in there -- no good
when i insert a disc i hear make the normal sound the drive should make

the computer has never been dropped, or gotten wet

it doesnt matter if i have a dvd or a cd in there -- nothing comes up -- even games. the autorun never comes up anymore. it used to be that when i inserted a disc i would get a popup asking me what i wanted to do -- NOPE not anymore

even when i use a program like nero or power iso -- no good

when i insert the disc it tells me -- please insert disc into drive e:


this is driving me absolutely insane and i really need it resolved -- can someone help me

the other questions i have is ---
could it be the optical lens not working?
and can i replace this drive if necessary

thanks ahead for your help
cheers