Yep. Here in the last line of this block is the correct entry for userinit.exe:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
AutoRestartShell REG_DWORD 0x1
DefaultDomainName REG_SZ GEORGE-6JXTPIR4
DefaultUserName REG_SZ George
LegalNoticeCaption REG_SZ
LegalNoticeText REG_SZ
PowerdownAfterShutdown REG_SZ 0
ReportBootOk REG_SZ 1
Shell REG_SZ Explorer.exe
ShutdownWithoutLogon REG_SZ 0
Userinit REG_SZ C:\WINDOWS\system32\userinit.exe,

Unfortunately the key that your MBAM keeps finding and removing "...CurrentVersion\Winlogon\Userinit" is not there, meaning that it has not re-occurred since last removed.
I think that there is another file being referenced in that trojan Userinit key, it is a rootkit and so is hidden. Possibly.
Please:
==Download [with IE only!!] the latest standalone version of Blacklight from ftp://ftp.f-secure.com/anti-virus/tools/fsbl.exe - Start it, accept the agreement and Scan.
==Download this file to your DESKTOP: http://download.bleepingcomputer.com/sUBs/ComboFix.exe
.....or this file: http://subs.geekstogo.com/ComboFix.exe
-IMPORTANT! : disconnect from the web, turn off your Antivirus, Antispyware and Firewall for the duration of this scan. Don't forget to reset them before you go back on the web!
- to run it dclick the Combofix.exe icon and follow the prompts to start it. When finished, it will produce a log, C:\Combofix.txt - post that log in your next reply.
A word of caution - do not touch your mouse/keyboard until the scan has completed. The scan will temporarily disable your desktop, and if interrupted may leave your desktop disabled. If this occurs reboot to restore the desktop.