I disagree with everyone here. There is no reason to go crazy. Simplicity is king.
IMHO if you have any malware on your local network, nothing you do will make you secure on your own machine.
Do fresh installs of ubuntu on all of the windows computers in your LAN, that should solve the problem.
This is not true. Even tho its not ideal to have malware on your local network, you can stay isolated from it. And running windows is not a problem;
As always, keep your OS fully up to date. Set the network configurations to "public" in windows so that windows will not share anything outwards on the network. And finally, get a firewall or learn how to configure the windows firewall and just deny everything coming towards your computer.
As for linux configuration it is pretty much the same. Keep it up to date and get a firewall, iptables will do but I recommend vuurmuur, which pretty much is a front-end for iptables.
When it comes to antivirus, this is a bit up to you. Honestly I haven't used a AV for years. Between the false positives and bullshit features, it just does more harm than good for me. The key is common sense and stop downloading and searching for crap you do not need.
I would also like to add that a VPN would help a lot with network interception. Get a VPN with good encryption standards and make sure that all your traffic is routed through it.
Oh and you dont need Linux/ubuntu on all your machines to have a secure setup, that just makes no sense.
Winwhat ?
Your story is kinda hard to read, but you should do a fresh install indeed, remove partitions,deep format.
If you want to make sure you best encrypt the drive afterwards.
And as d4rkcat proposed use another OS such as BSD or linux.
OP should defiantly do a deep clean of the machine(s) before attempting a secure setup. Boot a live CD and format all and every partitions and if you really want, overwrite it a few times for good measures.
As for encryption, I would defiently go full HDD encryption with True Crypt using a strong and long password (>15 characters).
but VPNs dont give me security in public wifis?
A VPN will give you some security when using public wifi's.
If you can not but use windows OS, do the following to make online banking very secure,
1. Get rid of all the existing malware in you're system
2. Get a key scrambler program
3. Use a portable browser for banking only (don't use this browser for anything else, not even for watching p0rn)
4. Keep that portable browser in a well encrypted file container
5. Alwys open that browser in a sand box
Not secure enough???
6. Do all the things listed above in a BSD environment which will run in a VM of course. And if you're really conserned about rats, get a good firewall. Good luck.
I think this is ridiculously overkill, but I guess some of these are okay if you think your system may be compromised. But in that case, why not just boot a live OS?
Just get a keyscambler encrypts the kea you press (anti keylogger) and run you OS via VM for regular use if your doing black hatting you will need more precautions in place
What good would a keyscrambler do against a kernel level hook? Or an infected browser? Or network sniffing? The list goes on and on.
VPN is a terrible idea.
If you are running windows it is a terrible idea.
So much for protection.
I dont even know what to respond to this, you have nothing to back up your claims at all.
There is however one little thing I would like to add. Buying a pre set up VPN solution is somewhat sketchy. I would recommend getting a VPS (Or in best case a dedicated server) from a serious and respectable hosting company and setting up a VPN yourself. Alternatively socks5 tunnels and set it up globally on your machine.