This is going to sound a bit rude but I'm really not trying to be, only straight forward.
Little Google goes a long ways;
As to before OS that's exactly what pre-boot is. It only does this if it's necessary because it can't remove malicious files being blocked by whatever means. It'll tell you some files couldn't be removed and prompt for a pre-boot scan to remove said files. That's about as good as you can get outside of certain AVs that you can manually trigger a pre-boot scan, which those won't completely cover what you're after anyways. The best course of action is to download, install, run update of MWB completely on each machine, disconnect them and run the scans multiple times. Once the number is 0 see if your problem is fixed. My dumb kids love to do things I tell them not to and have slowed my entire network to a snail crawl before due to infection causing me to place them on a bandwidth limited and scheduled VLAN. MWB single handedly cleaned each machine of a combined over 10k infections in less than 20 minutes (all SSD machines). Once my IPS stopped alarming me I knew it was all cleaned and I could then move forward with DNS limitations for them. Unless you got something more serious than kids clicking anything and everything they can imagine I would expect it'll work perfect for you too.
Thanks for the reply and expanation PP Mguire and no offence taken
I am running and have been running malwarebytes both official version and beta version along with other antivirus and malware scanners but with either no results or very confusing results..!
Its all got somewhat confusing... however here is what I do know:
1. formatted hdd then reinstalled windows 7 bought new router and setup with max security.. hacker was back in.. in no time at all and was switching on its wifi connection (possibly I connected to external hdd or device to connect to network that was not fully cleaned) but after this i did and experienced the following:
1. Cleaned down other laptop formatting hdd and reinstalling win 7 showed in local disk (c) files that I knew should not be there. this is without conecting to WWW or anything else (how is this possible?)
2. Was not allowed to copy paste files to usb - it would delete immediately on either take out or put in of usb after copy paste command to usb stick
3. My computer start up (While displaying bios options etc) has slowed very much (like something is working and taking too much time before windows starts to bootup)
There are more unusual things happening to pc's and I can only think that malware is present in other parts of computers hardware that will not be detected with general antivirus or malware scanners... don't know what to do?
Any further advice very welcome!