Try using 80pin cable if you are using 40pin cable to connect dvd drive.

Hi, I'm also having he same problem with a drive of the same model(SONY DW-Q120A).
All the reviews over the net rate it as one of the best, but mine does not work.
It showed the same symptoms - worked fine with all kind of disks, then stopped reading original DVDs, then stopped reading dvd media written using other drives, later stopped reading dvds burned using that drive itself, after a few days, stopped detecting dvds, stopped detecting the cds also finally.

If some one can help us out, please post in a response.....
thanks in advance.

get it repaired by calling your vendor.

Somewhere on net I found this :
   1. on Desktop click Start
   2. select Control Panel
   3. click on Administrative Tools
   4. click on Services
   5. browse your way down to IMAPI CD BURNING COM SERVICE
   6. right click (on IMAPI) then select properties
   7. in the middle of the window, it will say start up type. Click on the arrow to the right and select disabled.
   8. make sure you click APPLY

But according to me your lense is dying and you should go for new DVD writer... that just just Rs. 1000-1200 now a days.

SONY DVD RW, DVD/CD ROM, it works for 6 - 7 months correctly with no issues, maximum of 10 months, then is starts the problems. I have got writing problems, i always use sony disks to write Datas. When we go the dealer shops to ask about the services of sony, they will say sony servicing are too bad, if you got the problem within the warrenty period then they will look. Otherwise they wont!!! My SONY DVD RW, DVD/CD ROM is only 18 months old. Now onwards i suggest to every one, not to buy SONY DVD RW, DVD/CD ROM. They only got a good brand names, the other things are really bad. Buy some other burnner. If you ask to the dealers also, they will say Sony DVD RW, DVD/CD ROM is good, but buy other other DVD RW, DVD/CD ROM thats good for you. What is this means?