The LR4 catalog shouldn't be affected by the upgraded one as they're two separate files. Are you sure you're not trying to open the upgraded catalog? LR4 will not be able to open this.
If the LR4 catalog has been corrupted by some other action then you should go back to your most recent LR4 backup file.
thanks for your help.
working on it now. It now looks like it upgraded all of my LR4 catalogs ( I was in the process of editing and getting out about 8 shoots in LR4 at the unfortunate time I decide to give 5 a whirl) to the trial 5 version and now I can't open any of them. LR5 will let me look at that library but all other modules are closed.
In the past I have been able to go back to an older catalog but this time the older catalog is completely gone or looks gone. Only a 5 option is showing.
It sounds as if you are using the Lightroom 5 version from the creative cloud, and you don't have a subscription. The Lightroom behavior you are describing is what happens when you don't have an active creative cloud subscription. Upgrading catalogs from Lightroom 4 to Lightroom 5 does not do anything to the original catalog if you can find and start Lightroom 4, you should be able to start right where you left off. But any new files that you imported into Lightroom 5 will not be there. They will be on your hard drive and you can import them again. But you are going back to a catalog that was used up until you installed Lightroom 5. Hopefully, you didn't uninstall Lightroom 4.