Select the single files and open them into mp3tag. Select them all, then in the "ALBUM" field, enter the name SINGLES. Then hit the save icon. Now each of these tracks will have the album name "SINGLES" and show up as a 1000 track album. In addiiton, you can even auto number these tracks from 1 to 1000, just by selecting them all, choose TOOLS from menu, then autonumbering wizard.
edit: if you don't want to select all these singles to open in mp3tag, simply open your entire music directory in mp3tag. Then sort on the ALBUM column. This should allow you to see which tracks have no ALBUM name and you can then select those and do as noted above.