Well, I can't help you because I don't have a clue what you did to your computer, if you have a legitimate copy of PS with the Key code printed on the DVD or sleeve, that should still work if you re-install the software, it worked for me when I installed it on a different computer (only one computer at a time).
However, it may be time to update to the new PS CC and Adobe has an awesome offer for only $9.99 a month for both the latest version of Photoshop CC and Lightroom, that's only 33 cents a day and they update PS CC constantly with new additions etc. It have many new features over the old CS version like the Came Shake reduction filter and the ability to use the Camera Raw filter as a regular filter even for jpegs, really a bargin and defiantly worth the 33 cents a day.
https://creative.adobe.com/plans/photography?store_code=us