I am testing Computta now since more than a year. At the beginning there were a lot of warnings that the software may contain malware or virus. Now computta is whitelisted by the most common Anti Virus programs and still sometimes you will get a false positve.
I personally protect my PC with bullguard, a great software. The miner is installed at our son's PC since the early beginning of computta, no harm or whatsoever has occured. Since they do update the miner it even works more efficient.
For what I have experienced, computta is running smoothly and no intrusive or strange behavior ever happened to my PC.
After you have downloaded the miner from Computta you will first see a benchmark test, wich gives you a rough estimation of how much your PC will mine, then i recommend that you open the settings and choose how much power your PC should use to mine. For my PC the 90% option has turned out to be the best. I can easy keep working while the PC is mining.
How to get paid?
That's the easy and fun part! You login to your Computta Dashboard there you will see this:
A link to your wallet appears as soon you reached the payout minnimum. Transfer the balance to your Wallet and keep it there or withdraw it to your own BTC wallet right away.
After the payment is complete, you will see the above information.
All good, then go ahead and find out how much your PC will mine while you work!
You think your PC is too old for that? scroll up and read about Cryptotab.