We claim the ornamental design for a portable computer, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a portable computer of the present invention;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a first side view thereof;
FIG. 7 is a second side view thereof;
FIG. 8 is a perspective view of a second embodiment of a portable computer of the present invention;
FIG. 9 is a front view thereof;
FIG. 10 is a rear view thereof;
FIG. 11 is a top view thereof;
FIG. 12 is a bottom view thereof;
FIG. 13 is a first side view thereof; and,
FIG. 14 is a second side view thereof.
The broken line showing of portable computer is included for the purpose of illustrating environment and forms no part of the claimed design. Additionally, the unevenly broken lines in the drawings define the limits of the claimed design.