AageLaugesen

Perhaps you will be useful this online service. I read a lot of good reviews in Google about it. https://onlinefilerepair.com/en/photoshop-repair-online.html

I'm not sure what a pref file is...
CS2 is a nightmare and has had problems since it came out.  You probably will still be able to open them.  Just go into photoshop and open it through there, or right click (or ctrl click ) and use the open as option.

If this does not solve the problem then you can try to recover files using Recovery Toolbox Photoshop and then try to open them in Photoshop CS2. http://www.oemailrecovery.com/photoshop_recovery.html

Here is more about recovering Adobe Photoshop documents. Maybe it help you.

https://forums.adobe.com/message/6412766#6412766