I found your post looking for a solution to the exact same feedwater.com hijacking both Firefox and IE browsers. Every prior attempt through Windows Defender, McAfee, etc. to scan and remove were ineffective.
I now have apparently solved it, in my case, mainly through reverting to a system restore point prior to the infection.
I can't be sure that all of the following steps were absolutely necessary, but here is what I did specifically.
1. Force quit any browsers where the problem appeared as soon as possible, and without trying to close the browser windows directly or responding to any dialogue boxes. (performed via Task Manager).
2. Restarted the computer in safe mode. (I did this inelegantly by forcing the computer to power down without closing out of anything else). Out of an abundance of caution, since I had multiple accounts on the computer, I restarted in safe mode under a different account than the one that I was using at the time of infection.
3. Opened the system restore options and selected an existing restore point prior to the first appearance of the infection. (Control Panel; System and Maintenance; System; System Protection; System Restore.) (I did all this the same day the computer was infected so it was easy to know which one to select -- I had a restore point from the day before. If you are not sure of when the infection occurred, search your browser histories for the first appearance of "freewater" and select a restore point prior to that).
4. Following restart, since I happened to have Safari on my desktop (even though I'm running Vista and principally use Firefox, which was hijacked), and since I didn't know yet whether the other browsers were clean, I used Safari to download and then installed the MBAM/Malware Bytes program. Upon finishing the installation and before starting up MBAM, I unchecked the box authorizing MBAM to check for any update on its first launching so that it wouldn't try to access the internet to search for or download an update.
5. Ran MBAM and removed any offending results. Following the required restart, I then manually authorized MBAM to update and then and ran it again, and it came back clean.
6. Because the system restore point was prior to my last Windows update, I checked for and installed any important Windows Updates, including updates the the Windows Defender library so that I made sure to have included any recently identified malware.
7. Following the required restart from the Windows update (and still using the Safari browser, although I don't know that it's necessary) I downloaded (or re-downloaded) the most recent version of Firefox.
7. Following the required restart resulting from Windows update, I was able to re-launch Firefox without any re-appearance of the freewater re-directed sites. (Note, if when you restart Firefox, it asks about restoring a previous session or previous tabs, select "Start a new session instead." If, on restarting, it is clear that Firefox is launching two or more tabs (as it does often after an update), try and close all but one tab (the tab announcing "you have been updated"), especially if a tab is taking any time to load. )
Hope this helps!
