Please Help : Certain files take VERY long to open

Hi all, I am not a Corel Draw user myself, but I am trying to assist a client with their CDR issues.

The clients Artroom used Corel Draw 7 and purchased 1 x Corel Draw X3 a while back. So they are actively using v.7 and X3.

Recently they have been experiencing problems with certain files. Files takes up to 10min to open and save.

As I understand, this is files created in Corel Draw 7. They re-open it in Corel 7, make changes and save it as Corel 7 compatible. Then the next person might open it in Corel X3, and save it again as Corel 7 compatible.

Basically, they are just adding to older projects and re saving.   

The users in the Art room are making it quite hard for us to assist, because they are terribly set in their Corel 7 ways.
I feel that using different versions might be causing the problem?

We also put in a new machine for the 1 x specific user who experiences the most issues. Windows 7 Pro, 2.8GhZ, 4GB RAM etc.

Any suggestions will be greatly appreciated, as this is issue is being blamed on hardware, network and everything except a corel draw or user issue.

We have re-installed Corel Draw (both versions)
Patches updated

Kind regards,
Nadia