I managed to recreate the problems detailed here and here. I tried to use Notepad to open a .lnk file. Now all shorcuts appear as .lnk files, and open in Notepad. This isn't an uncommon problem and there are numerous solutions floating around, including in the thread I linked. Unfortunately, most of them involve using regedit or otherwise modifying the registry. I don't have admin access on this computer (work machine) and registry access has been locked.
Do I have any prayer of fixing this without admin access? Tech support was less than helpful, and it will be weeks before I can see them in person..
This is using Windows 7.