Lightroom5 reinstallion

Are you trying to install or use Lightroom v2 with a newer Mac OS?

Probably not going to work

On the bright side, the new version of LR is not that different from the old - just more powerful with many more options.

You should still have a copy of your old catalog and an updated LR version will "update" your catalog and leave you the old catalog.

If I read you correctly, your Mac OS was reinstalled and a copy of Lightroom came with that installation?

I don't believe I understand what a "2.0 version" is. 

Are you referring to Lightroom, Creative Cloud or something else.

Send through screen shots will help.

If you do so, please use the "Insert Photos" icon in the post reply window, NOT the "Insert/edit link" icon.

Now, with the reinstalation, it just came in a new version, which I dont even know how to start

How did you re-install? What did you re-install? Please be specifc, tell us exactly what installation file you used, where you got it from and how you installed it.

What new version? Please be specific, give the version NUMBER.

Consider these points-

Lightroom v5 (the old Perpetual version) is not supported by, or available as a direct download from Adobe.

You may be able to download v5 through this independent site- 6.14 download VERY IMPORTANT INSTRUCTIONS 

You would need your Serial Registration number.

*If your Mac uses either Catalina or BigSur OS, then you cannot install LR5. (Mac is 64bit only. LR5 installer is 32bit)