I used to use PS7 then upgraded everything including computers.  Now I get out of ram errors all the time. Not Happy!!  Ideas?

I used to be able to minipulate huge photoshop files.
Now I can't even get one to go from 20 to 50 gig!
All I get is this out of ram error.
I have a 400G scratch disk and well over optimum on all settings!

It would be necessary that you have to use "Adobe Creative Suite Cleaner Tool". (see Use the CC Cleaner Tool to solve installation problems | CC, CS3-CS6 )
The order varies depending on your individual needs:
1. Maybe you have to activate/deactivate, so please have a look there:
2. Sometimes, we know in the meantime, the "opm.db file" is the culprit. In this case you should delete it.
3. Did you already try "uninstalling and re-installing"? Be careful with (de)installing aso. by (de)installing by your own resources. As much as I regret it and as strange as it may seem I fear it's a challenge for Adobe's Creative Cloud Cleaner Tool. Sometimes - for whatever reasons - CC doesn't "want" to work. In this case you should CC completely delete and reinstall by help of Adobe Creative Cloud Cleaner Tool. (A try to uninstall by own resources is not enough!)
I quote: Adobe Creative Suite Cleaner Tool helps resolve installation problems for Adobe Creative Cloud and Adobe Creative Suite (CS3-CS6) applications. The tool removes installation records for prerelease installations of Creative Cloud or Creative Suite applications. It does not affect existing installations of previous versions of Creative Cloud or Creative Suite applications.
Please use: http://helpx.adobe.com/creative-suite/kb/cs5-cleaner-tool-installation-problems.html   and follow the prescribed sequence of operations
4. If necessary and for further questions click through http://helpx.adobe.com/contact.html or http://helpx.adobe.com/de/contact.html and if "open" please use chat, I had the best experiences.  The chat button is activated as soon as there is an agent available to help.