The idea that you can defeat some mysterious, invisible key-logging opponent with copy/paste, mouse clicks, back-spaces, and all that kind of key-dancing is ridiculous. You would have zero way of knowing exactly what kind of data is being logged, how it's being logged, etc. Having written key-interception hooks myself (for legitimate reasons), I know it's trivial to record all Windows messages. Do not trust that an attacker wouldn't learn everything you enter.
Instead of imagining you're dealing with a key logger, you should suspect the whole machine has been compromised. Dealing with a compromised system is pretty much the same, regardless of what kind of compromise it is.
Assuming this is your computer, take it off line immediately. Unplug the network cable, disable the wireless card. Do not let the machine reconnect to the Internet until after you've neutralized the malware.
If you've ever entered your credit card info into this machine, contact your bank's "lost or stolen card department" and tell them what's happened. Do this immediately and request a new credit card now. You don't know if the data leaked, but you should take no chances.
Assuming you've used the compromised machine to enter credentials to log into web sites or other places, you'll need to change those passwords now. Use a new, trustworthy machine to log in and change your passwords. This would be a good opportunity to obtain and use a password manager.
Make an inventory of the data on the compromised machine, and use a USB mass storage device to back it up. Be careful if you back up any programs, as they might carry infections - if possible, plan to download new copies from the Internet. Also, see if there's a way to back up any software licenses (Office, Windows, etc.) Consider bringing your machine to a professional dewormer, who might have a way of preserving the machine without losing those licenses.
If you suspect that your credit card was misused, this is the time to consider contacting your local authorities and reporting the attack. Theft by computer is a crime, and they should treat it as such. But don't expect much from them - they might not have a competent digital forensic analyst; they might not consider your problem important enough to investigate; or they may want to place your case in a queue where your computer will sit in an evidence locker for six months.
If you're still handling the compromise yourself, it's time to reimage the machine. DBAN is a good tool to use to thoroughly wipe your hard drive; but be aware that it will destroy any 'recovery partitions'. That's good for your security, because you don't know if they were compromised by the attacker; but it might make recovery hard if you no longer have an installable OS image. You'll also lose any licenses you may have had stored on the machine; this is where having backed them up is critical, and why I recommend using a professional.