I think I am going to put a switch on it and turn it off when I am not using it.
I assume you mean on the power input. That means it will have to power up and download guide each time. That's a long time to wait to use the box.
Which versioin of Netbox, 2 or 3, & which model (is it PVR)?
Just a heads up - I had a 'clicking' noise coming from my Nextbox 2 HD PVR (8642HD), and it turned out to be the hard drive...it was overheating due to an ongoing technical issue and was failing.
@mfait is correct about the guide download - your box could take up to 10 minutes each time you 'flip the switch' to become useable again. Best to continue troubleshooting and fix the problem.
If it's a PVR (8642 or 9865), it has an iHDD (internal Hard Disk Drive). This drive does make some noise, but it's usually a whirring sound, not a clicking noise. As mentioned above, if it's clicking, then there is usually an issue with the HDD and ready to fail.
The HDD is accessed when the unit is on because it's recording the channel you're on (pause live TV), unless you change to channel 950 for example which doesn't record. But even when the PVR is "off" (actually standby), there are firmware updates, IPG updates, etc that can cause the HDD to "come alive". A regular STB like the 4642 should be silent.
You should always have your PVR in a well-ventillated area to preclude overheating. Do not place anything on top of the PVR. It's usually a good idea to plug any PVR into a UPS to preclude head crashes and to reboot if possibile using "Settings - Troubleshooting" instead of unplugging.