cant register says Input error: Invalid referer  and captca error

There's is actually not much to the process:
1. Download the Windows client (I haven't tried other) from OP
2. Unpack it into a folder on your PC.
3. Start zetacoin-qt
4. Stop zetacoin-qt
5. Open Windows explorer and enter %appdata%\Zetacoin in the address bar
6. Create zetacoin.conf there. If you are going to mine on the same machine, you only need 127.0.0.1 in rpcallowip. If you will mine from another machine on your network, enter an IP of that machine or network IP wildcard as shown in my example
7. (Optional for better connectivity) On your internet router, forward port 17333
8. Start zetacoin-qt (and wait for it to download the blockchain)
9. Start your favourite miner, pointing it to the IP of the machine where zetacoin-qt is running or to 127.0.0.1, if on the same machine.

3-4 blocks per hour @ 20GH/s on difficulty downcurve; 2-3 on the upcurve. An extra bonus: no pool fees and an occasional transaction fee paid to you with a block.

Zet diff is changing so quickly, that solo mining cant be predicted and/or properly calculated.
You can take avg block diff from 500 blocks and calculate in any bitcoin calculator.

My P2pool ZET payout strategy is 12hrs and/or 100 blocks so it will take while to get "full" payout, but it is steady. P2pool node have only 3 block payout so you will get full payout really quick, but if you have low power and/or be unlucky you will not get paid for all blocks found in pool.
My code is hopper-unfriendly ;]

Also P2pool advantage is that block found is propagated via pool nodes too, which can reduce orphaned blocks. When you mine solo you propagate only through nodes connected to your zetacoin daemon.

ZET is a only SHA listed that is more profitable than BTC.

+1

I'm a SHA guy myself

It doesn't.  However our "cousin" site at www.wheretomine.com can help

This pool does not let you register - captcha missing error it seems....

Same problem here! I thought maybe it was my slightly out-of-date IE browser (IE9), but I just tried with an updated Firefox browser (23.0.1) and also an updated Chrome (29.0.1547.66) and got the same error.