My internal CD/DVD player/burner has gotten to where it doesn't recognize DVDs. I recently put in some CDs and it played those just fine and downloaded them just fine. It won't recognize DVDs most of the time though. Most DVDs that I put in are not even recognized by the computer when I look at the D-drive on my computer. It is as if there is nothing in there. The player just cycles and cycles like it is trying to find something and then quits after a little bit when it gives up looking.
Recognizing CDs, but not DVDs. Is this a hardware or software problem?
Could be hardware and DVD Rom drives are cheap and not to hard to replace.
If you want to make sure then try running your anti software program and any anti spyware programs you may have. I heard about this on the radio yesterday.
http://www.doublemyspeed.com/home.html?ref=DoubleMySpeed.com
Without being there to test a few things myself I can't say for sure, but from the given data I'd say almost certainly hardware. The only way that could be caused by software would be if your Windows had a problem at the most fundamental, basic level, perhaps caused by a hard drive corruption or a virus.
One way to work around it really easy and for cheap is to get a USB disk drive. They make them USB powered these days, don't even have to plug them into the wall. The only cheaper way would be to get an internal disk drive and install it yourself, but of course that's not as easy as USB plug-n-play.
One way to test the hardware is to try to boot from a Linux live DVD. If it will boot it's probably a Windows software problem - if it won't boot it's probably hardware.