Stymied at Step 4 of Malware Removal Guide

Hi,
I am doing my best to follow all the steps in the Malware Removal Guide, despite feeling exposed & vulnerable.
I am at step 4: disable disk emulation software.
I have downloaded Defogger from the bleeping computer website, but when I go to open it, I get this security warning: this file does not have a valid digital signature that verifies its publisher.
So, the freak out level has gone up somewhat.
Please advise.

 

"Okay" she said, nervously.:eek
I see this is a trust excercise, so trust I will.
Thank you and will be back with logs soon.

 

Hi, again,
I have finished with my scans and am sending my logs.
I have Trusteer Rapport installed on my computer and a couple of weeks ago I noticed it reported that it had activated anti-keylogging when I signed into my yahoo email. I didn't think anything of it because the report says the following:

"The following password submissions were protected by the character replacement feature. Trusteer Endpoint Protection has prevented access to the original keystrokes from most common keyloggers. This does not necessarily mean you have keyloggers on your PC. However, applications on your PC that tried to log keystrokes while you were entering information to the websites below have failed."

And then it lists the date, time and web address for each instance where anti-keylogging was activated.

I assumed it was protecting me, but then a credit card I use online had fraudulent purchases, so I checked the report again and saw that every time I attempt to log in to my email account anti-keylogging gets triggered. And, the last time I used that credit card online, I had to go into my yahoo email to retrieve the log-in info for the website I made the purchase on. I used a link from within my email to go to the website and make the purchase. I made the purchase and a fraudulent purchase was made the following day.

And, now, here I am. Please help