What computer operating system are you running Premiere Elements 11 on? Can we assume that you have the latest version of QuickTime installed and that you are running the program as Administrator and/or from a User Account with Administrative Privileges?
What do your computer resources look like?
Are you saying that you have created two DVD-VIDEO on DVDs to date?
Focusing on the projects that will not open, did you move any of the media that went into them to a new location after the save/close of the projects?
If we look at this from a damaged project angle, then you might want to review that Adobe troubleshooting on this type of situation:
From the point of review of new and old projects not opening, let us try first flushing the preferences. Assuming Windows 7 or 8 64 bit....we want to delete the Adobe Premiere Elements Prefs file. The path to it is:
Local Disk C
and in the 11 Folder is the Adobe Premiere Elements Prefs file that you delete. If that does not work, then try deleting the whole 11 Folder in which the Adobe Premiere Elements Prefs file exists. Make sure that you are working with Folder Options Show Hidden Files, Folders, and Drives active so that you can see the path.
Also, check out the Scratch Files to assure that you have them set to save to a hard drive location with adequate hard drive space to accept them. See Edit Menu/Preferences/Scratch Disks where you will be able to see where the Scratch Disks are directed to as well as the free hard drive space at that location.
Just how large where these two DVD-VIDEO projects that you completed immediately before the new and old projects not opening problem hit?
Please review. We will be looking for your follow up.
Thank you for your help and answering my post. Rebooted and problem solved!
Very much appreciate the follow up with the great news that the problem is resolved.
Continuing success with your projects. Do not hesitate to ask if you have any further questions about your Premiere Elements workflow. We look forward to the opportunity to help.