computing basic i need to know

How can you move files if you turn the computer off?

I think what the person meant to say that when he was transferring a large file which takes some time, and somehow the the power source to the computer was disabled.

Back to the question. So if you didn't save it, or just cut and paste, it may not be recoverable without a software that searches for fragments and puts it back together. Unfortunately though, some documents might not be recoverable.

Next time don't cut and paste, just copy and paste it to a new place, then come back to where you copied it from and delete the original file. So even if the power goes out, the original file on the computer is still there.
If you already did this, you're ok.

what i mean is if you start transferring a document to a different file but you have a power cut before its done could it be permanently lost

It depends on the type of move, and the operating system.

Under Windows, if you move a file from one directory to another on the same disk, the only thing that gets changed is an entry in a table that says where the file is supposed to be. If you turn off the computer while this change is taking place, then you might corrupt the table. The file will still be on the disk, and you should be able to recover it.

If you move a file from one disk to another, it actually performs a copy and then a delete. In this case, you would not lose the file, since the copy has to be completed before the operating system will delete the original file.

I believe that most other operating systems perform similarly, but I cannot guarantee it.

Well it depends on the file system.

Let's see what happens in the hardware area.
Without a proper shutdown, the memory DIMM's is not refreshed as it ought to do, and without a constant refresh, it will loose data. Without that in mind, what happens is that the data will be replaced with static or garbage.
The hard drives will run a bit longer than the dual in-line memory module so if it is written onto your computer disk, so the direct memory access controller will keep running and will write the "garbage" fed by the DIMM, so it will keep reading but what it's reading is corrupted data. The DMA will keep reading data from memory, but it has no idea that this data is corrupted.
Although the entire file won't be corrupted, some of it will be due to the decrease the refresh cycle of your RAM, it is apparent that some corruption still occurs.
The chance of data loss increases in a power failure when you are using an encrypted file system.

If your hardrive is old, added to the corrupted data, there is a chance you'll break it, so next time you try to boot up, it won't.

right problem is this is on a school computer they have hard drives and everyone logs in on different computers they have hard drives and they all run off microsoft not windows 7 they run off something earlier than windows 7 its happend a few times in the year where we've been moving our documents to a different file on document but for some reason ive got some files and lost all others