I believe you've just hit on a "new" problem that I hadn't been aware of. Prompted by your question, I just tried to play a few DVDs finalized on my own Pioneer 520 recorder in my newest PCs. My experience reflects yours: absolutely no go in any software player I have installed. This is not good news.
After the 520 DVDs failed to play, I tested DVDs made on all my different recorders going back eight years. None of the DVDs burned on recorder models that don't finalize with an auto-run menu. I tried discs from a Pioneer 510, Pioneer 520, Pioneer 531, Pioneer, 540, 550, 560, JVC DRM100, and JVC DRMV5. All of these create a DVD menu that doesn't auto-run upon loading: it needs to be invoked with the Menu button of the player. About half the DVD recorders ever sold create this type of manual menu, and half create auto-run.
The "manual menu" discs will appear in Windows Explorer and My Computer, when opened I can see the usual VIDEO-TS folder and the expected files inside that folder. But the discs won't play in Windows Media Player, KL Player, or Media Player Classic. Attempts to drag the discs or VIDEO_TS folder into the open player windows results in either a black screen or an application freeze. Utilities like the SlySoft suite randomly insist the discs are defective and won't do anything with them.
I never had an issue playing or using these discs in my old Windows XP systems, and these discs all still play fine in Apple Macs running various versions of OS X from Tiger to Leopard to Lion. These discs play normally in all my Philips and Panasonic DVD players, my Pioneer and Magnavox DVD/HDD recorders, and an LG BluRay player.
The ONLY systems that will not handle these manual-menu recorder DVDs are my newest Samsung and Lenovo laptops running under Windows 7. There seems to be some odd interaction between Windows 7 underpinnings and certain types of recorder-burned DVDs. I can't imagine where to begin troubleshooting this, since it isn't consistent: Windows 7 *will* allow media software to play DVDs burned with auto-run menus (Magnavox 513 or 2160, DVDflick, AVStoDVD)..
I'm glad you brought this to our attention, Rob_Chew, or it would have been ages before I thought to check my old DVDs in a new PC. I can't say I'm glad the problem exists, 'cause I'm completely stumped.
Anyone else notice this issue?Edited by CitiBear - 1/31/13 at 11:42am