I've purchased LR5 online, downloaded it and now can't open it.
I'm being asked for a serial number, which has been provided. I'm also being asked for the original S/N??
I was only given have the one... this is the prompt I get back after entering the first "This is an upgrade serial number.The serial number from your previous version of Lightroom is reqiured'. It's a new computer and I've never owned LR before......
Can someone please tell me whats's going on here?
Yes. You bought an "upgrade" version of Lightroom. You wanted to buy the non-upgrade version. You'll have to get in touch with Adobe's Customer Support and explain the problem and get them to help you.