My PC is reading any cd as empty cd
Note : it is reading dvd's normaly
Is their a problem in the hardware or in the software ?

Reseat all cables, reseat both ends of the data cable then, try reloading the drivers you can get them form the manufactures web site. If this dose not help replace the drive

A combo drive actually uses two different lens configurations for the cd and for the dvd. It's possible for one to stop working and the other to still work. Try buying a cd/dvd lens cleaning disk, their not expensive and you should be using them on occasion anyway to keep the lens clean. I like to use canned air to blow out the drive first with the tray open To get rid of any dust or hair buildup. Keep the can upright so it doesn't blow freezing liquid and use short bursts. Then run the cleaning disk as per instructions.

Forget about downloading software from the manufacturer since this is not normally needed except for DOS. If you want to reinstall the drivers, just open the Device Manager, find the drive in question and right click selecting "uninstall" then reboot the PC and Windows will reinstall the generic drivers it uses for all optical drives. This works great if for some reason the drivers became corrupted. If your using XP just hit the start button, find My Computer and right click selecting Properties. Select the Hardware tab then Device Manager and finally DVD/CD-Rom Drives. Locate the drive by name and right click uninstall and reboot. Be careful if you have Daemon Tools installed or another Virtual Drive, you do not want to uninstall those drivers since they are not Windows generic.