Contact Adobe Support with your CS5 serial number. As you've paid $700 for the software, you might as well take advantage of their free 24 hour support service.
1. I'm having trouble downloading or installing my software.
2. I'm trying to use a single-user product I bought from Adobe or another merchant.
Try this first:
Most common solutions are found here:
Downloading and installing Adobe products
Still need help?
Give us a call at 800-833-6687 and follow the prompt for "installing" to talk to an agent or have an agent call you back.