Down loaded El Capitan on my I Mac.I cannot find it to open.

Not from this site you didn't

It doesn't look like that PVR was designed to interact with Macs. Of course, there are workarounds, if you're ready to dive into your Mac:
https://beyonwiz.com.au/forum/viewtopic.php?f=5&t=820

Try restarting your system.
You should also upgrade to OS X El Capitan, 10.1.1

The current version of OS X El Capitan 10.11 is
free to download from the Mac App store.

install El Capitan

Hi Felix

Pretty simple really.... once you get the iMac opened!
See below

Simply find the existing hard drive, disconnect and slip it out.
You might have to remove a couple of screw in locating studs from the old drive and add to the new drive.
The connectors should match up with the existing cable.
Called SATA (Serial ATA)
The temperature sensor is stuck to the outside of the drive, carefully peel it off and stick it on the new drive.

Use Carbon Copy Cloner (CCC) to make a clone copy of your existing drive or install a new OS X (Downloadt off Apple Site)
Good Luck

I'll assume you know that Maverics, Yosemite OS X are free to download. And the latest El Capitan is due in Days.

Resources:
Mac Backup Software
intel iMac HD install