"It is possible that the crook did all purchases before I changed passwords."
Your first post was 12/26 in which you stated someone bought the first watch using your account, listed and sold it on your account. In that post you said you changed your passwords.
The second watch was purchased by someone using your account on 12/28. You said eBay removed that listing. removed.
By your own accounting, the second watch was purchased by someone using your account after you changed your passwords.
I have provided the links to all your post regarding this situation - so others can read and perhaps offer something.
Go back and read all your previous posts and all the answers you received.
First post 12/26/12
http://answercenter.ebay.com/question/Trust-Safety-Safeharbor/Need-Advice-Listed/900368278?#msg901651519
Second post 12/26/12
http://answercenter.ebay.com/question/Trust-Safety-Safeharbor/Advised-Start-New/900368331?#msg901651757
Third post 12/27/12
http://answercenter.ebay.com/question/Trust-Safety-Safeharbor/Follow-Situation/1000361515?#msg1001620456
Fourth post 12/30/12
http://answercenter.ebay.com/question/Trust-Safety-Safeharbor/Working-Details-Account/900368948?#msg901654661
Have you Googled how keystroke loggers are installed on one's computer? Have you Googled how to remove these?
1. Everything I have read recommends changing passwords from another computer - not on the infected computer.
2. Most everything I have read recommends backing up files to an external hard drive and re-setting the infected computer to its factory setting and reinstalling files onto a completely "clean" computer.
Many people can't perform #2 on their own hence the advice to hire a professional to do this.
"It was not possible to change passwords from another computer. Now I have a new bank account, new debit card, new passwords, run scans from two different providers, called e-bay, called paypal, and I think I have covered my bases."
If the keylogger is still imbedded in your computer, it's very possible this will happen again.
Let's hope not for your sake and the sake of the unsuspecting sellers.
Woof! Woof!