it always showed the complete history, but now it only shows updates going back to March 2014. (I wonder if all the various programs that I installed and ran over the last two months trying to solve the DVD play issue may have deleted the history?)
If this was the case the operating system would have been corrupted resulting in a non bootable computer.
Regarding my AV program, I run only one: ESET Smart Security. I have other programs such as Malewarebytes, but they are used only for on-demand scanning. I am well aware of the problems that may arise from having two or more AV programs running at the same time. That's why I have only one.
NOD32 v3.x FiX 1.1 by TemDono (Free Updates - Expire in 2050) 3/16/14
NOD32 v3.0.642 FiX1.2 by TemDono (31 days remaining forever up 3/16/14
ESET Smart Security
(4.0.314.0) ESET, spol s r. o. 4/12/09
Having Malwarebytes installed is fine and it`s use is indeed recommended, there are however two other AV programs installed apart from ESET and running or not there is the potential for conflicts, if you do not use them why in fact are they even installed, the same for all the DVD software variants, it is your computer and entirely up to yourself but if me I would get rid of the lot and start afresh so as to try and rule out software conflicts as the cause.
Regarding the comment from Twisterr: as I mentioned above, I just replaced one optical drive with a brand new one, so a "worn out" laser is not the issue. The "worn out" laser theory also doesn't explain why the problem appeared at the same point in time for both optical drives (one new and one older).
I concur, the drives burn, play and read media albeit when done manually but it would appear to prove that there is nothing amiss with the lasers on the drives.
Frankly, I don't know what else can be done. As mentioned before, my last resort is to restore to a known malware free image taken of the entire C:\ drive from March 2012. My important data is backed up to an external drive, and except for the minor inconvenience of updating Windows XP and a handful of other programs, I don't see how I can be any worse off than now.
Again it is entirely your choice if you feel that nothing more can be done.
I am puzzled by the missing XP updates and it is a pity that we did not know this sooner as it is entirely possible that this and the lack of auto play are in some way connected.
Regarding the use of the back up image, would you be able to lay your hands on a second HDD and install the image to that, just a thought and I realise that it may not be possible.
Edit: I checked for firmware updates for my two optical drives by going to the Liteon website link you provided. Both drives have the most current firmware update.
As you can see by the details below both are dated 7/1/01 some 13+ years ago, if you refer to reply #282 here you will see that there is a firmware available that was released on 03/24/2009
Category Driver Make Driver Details Driver
Status DVD/CD-ROM Devices ATAPI iHAP322 8 7/1/01
DVD/CD-ROM Devices ATAPI iHAP422 W 7/1/01