You are aware this whole thread is a bait, right? /Right/?
The only solution to removing a hacker from within your computer is downloading excessive amounts of ram.
http://downloadmoreram.com/
By downloading more RAM, Random Access Memory, the Hacker doesn't know where your memory is located due to it all being Random. You will no longer need a storage device such as a HDD or SSD. All you need to do is download infinitely more RAM.
Voitaisko me jo puhua Suomea? En osaa puhua Englantia.
IF, and only IF, you ACTUALLY need help with this:
1. Unplug all the computers from power.
2. Plug one of the computers to power.
3. Boot up the computer, insert LEGIT windows installation disc and shut it down.
4. Boot it up again, and boot up from disc. If your computer continues even to Windows logo/loading/login screen, power it off and try again.
4b. If you're unable to boot up from the disc, send the computer to be fixed in a computer shop (Or wherever the hell you want to).
5. When the boot asks you to do something, select clean install, that is, /reinstalling the os without keeping any existing data/.
6. Do 2. over for the rest of the computers.
And you're correct; your English isn't bad. It's fucking /HORRIBLE/.