My driver for sony cd rom cdu5211 is lost and now my CD ROM is not reading any type of CD.

It depends on what Operating System you are using.Windows Xp have all the drivers for Sony and other brands of CD rom drives,same with Vista and win7.Just go to the control panel,click the hardware manager and the drop down menu will show the hardwares of your CPU.Look for the cdrom driver and see if it has the yellow baloon with exclamation-meaning it has an error or the driver is not installed.You can go to sony website and type in your cdrom drive model and it will give you the driver for it,download the software.If the software is detected and ask you to install it,click "yes".After the process is done,test it by putting in a music or picture cd,make sure the drive is clean too cause reasons why cdroms don't read is because of dirty laserheads.Buy yourself a cdrom lens cleaner disk,it helps me many times.