If she is, I suggest that she does this:
Write to Technoworld, and tell them that the computer has been returned by Acer and now appears to be functioning correctly. Say that you reserve your rights under consumer law, but that in view of their failure to recognise your rejection of the machine, and their failure to pay a full refund, you are prepared to accept the computer on condition that they acknowledge your right to reject it if it becomes apparent that the fault has not been properly rectified.
Tell them that unless within 14 days they acknowledge your right to reject at a later date you wish your previous rejection request to be reinstated.
What you're aiming for is a full reinstatement of your rights immediately prior to the first rejection notification. You don't want a situation in which the retailer subsequently tells you that you may no longer reject the machine if the fault reappears.
On the other hand your daughter might simply decide she doesn't want this computer, in which case she must ask Technoworld to comply with the original rejection notification.