Have you subscribed to CC and installed the CC Desktop app? That's the only way to get the CC version of Lr 5 - it's downloaded and installed via the app.
That said, Lr 5 is still available stand-alone - you don't need the CC version.
yes, subscribed and installed on desktop, then installed the cc app and LR 5 on my laptop. the laptop has LR 4 and will not update to LR 5.
Does your laptop meet minimum system requirements?
What - exactly - happens when it fails to update?
Lightroom 4 should not interfere with the installation of Lightroom 5 from the creative cloud. They are separate applications. What happened when you tried to install Lightroom 5 on the laptop?
What operating system does the laptop use?
How much RAM?
How much disk space?