Try restarting the computer with the new keyboard Plugged in>>> Sounds likely it is the system that is slow and not the keyboard itself. When You have a slow system for whatever reason there seems to be a delay in typing and showing on the screen, and if you start typing too fast it may start making a singular beeping sound.... try that first and see what happens
. Will come back and check up on response then go from there 
As far as your erased work goes, im still trying to get the picture
if you accidently copied it into another document, then click the cursor at the beginning then holding the right mouse button, move down and to the right, or until you have highlighted everything, then where it is highlighted ( in the blue) RIGHT click and a drop box should pop up, then select copy or cut... Open a new document, left click cursor, then right click and select paste...
Sorry wish i could help some more, just not sure of the picture i have in mind is what you are trying to explain 