Acer TravelMate B113-M Service Manual page 129

From top to bottom, pry the left side of the upper case to release the latches.
5.
Continue to pry to release the top and bottom side latches.
6.
CAUTION:
A cable is still connected under the upper case, do not completely lift the upper case.
5-33
Figure 5:42. Removing the Upper Case (2 of 3)
Figure 5:43. Removing the Upper Case (3 of 3)
Service and Maintenance