Hi and welcome to Daniweb forums :).
Can you please do the following.
===============
Run HiJackThis then:
1. Click "Open the Misc Tools Section"
2. Click "Open Process manager"
-
Next, while holding down the CTRL key, locate (if present) and click on (highlight) each of the following:
C:\WINDOWS\lsass.exe
Now double-check and make sure that only those item(s) above are highlighted, then click "Kill process". Now, click "Refresh", check again, and repeat this step if any remain.
===============
Scan with HijackThis and then place a check next to all the following, if present:
F2 - REG:system.ini: Shell=explorer.exe C:\WINDOWS\system\lsass.exe
F2 - REG:system.ini: UserInit=userinit.exe,C:\WINDOWS\system\lsass.exe
O7 - HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System, DisableRegedit=1
Now, close all instances of Internet Explorer and any other windows you have open except HiJackThis, click "Fix checked".
===============
Locate and delete the following item(s), if present. Make sure you are able to view system and hidden files/ folders:
files...
C:\WINDOWS\lsass.exe
C:\WINDOWS\system\lsass.exe
-
Note that some of these file(s)/folder(s) may or may not be present. If present, and cannot be deleted because they're 'in use', try deleting them in Safe Mode by doing the following: Restart your computer
After hearing your computer beep once during startup, but before the Windows icon appears, press F8.
Instead of Windows loading as normal, a menu should appear.
Select the first option to run Windows in Safe Mode hit enter.
-
Reboot.
===============
After rebooting, rescan with hijackthis and post back a new log. Please let me know how your pc is now.