Thanks roncerr, yeah, defender offline is something that has been suggested to me so I'll try it. Tbh though, I think damage limitation is needed. my PC is currently becoming a nightmare. Mail and live movie maker have disappeared and windows live essentials says they're installed. I installed mail again but it's not installed. I can't install any windows live programs now, it lists them all with big green ticks saying they're installed and just a close button. If I try to delete the live mail folders showing up in program files x86 and program files, it says you require permission from trustedinstaller to make changes to this folder. I'm getting that on a few programs. There's so many messed up things now I think my only choice is to format and do a complete Windows 7 reinstall. It's been a long time coming anyway, it's just a PITA to go through the backing up and reinstalling stuff. I'll do a ghetto backup and manually transfer important stuff to my laptop and nuke this C drive and reinstall windows.
I found thousands of .eml files in app data, so it looks like my emails are intact. So I presume I can import them into windows live mail on the new windows install.