Corel Draw opens files very slow

Hello everybody!

I have this issue with Corel Draw 12 and any help will be most appreciate:

When I open a file it takes about 3 to 10 min, even more. I make rubber stamps so my files contain circles with text fitted on it and no more than 10 rubber stamps models.

I reinstalled Corel Suite but no hope.

If I create a new file, draw a rectangle (or a rubber stamp) and save it, the next time this file opens instantly. If I open an old file, after finally opens, I delete everything in it and save it, the next time it will take several minutes to open. Also, the empty file is about 700 KB long, comparing to a new empty file which is about 12 KB long.

Please help! 

The Corel stuff no longer supports Corel 12 (even if I've seen the same problem on other forums, reported  for higher versions, with no real solution) so you are my only hope.

Thank you!

NB: Old files are the files created before reinstalling Corel Suite; and they are a lotSad