my computer crashed. After fixing it, I have reinstall my CS3. After updating the OS, I can't reinstall my old CS3. How do I go about this?
Hardly considering CS3 was made free. Where are you trying to download from and have you removed the previous installation.
CC is very affordable depending on the package you go with and if you're a student.
>CS3 was made free
Not so... the activation server for CS2 was removed, so people with a CS2 (or earlier, but NOT CS3) may download a special version
>After updating the OS, I can't reinstall my old CS3
What IS your new operating system?
If you have a 64bit computer, Photoshop Elements 15 and Premiere Elements 15 run on Mac Sierra or Windows 10
If 32bit, you MAY still be able to buy version 14 at Amazon Amazon.com: Adobe Photoshop Elements 14 & Premiere Elements 14 Multi-Platform 14 [Old Version]: Software