We claim the ornamental design for a portable computer, as shown and described.
FIG. 1 is a rear perspective view of a portable computer of the invention;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a rear perspective view thereof in an environmental use;
FIG. 9 is an enlarged view of the area defined by circle 9 of FIG. 1; and,
FIG. 10 is an enlarged view of the area defined by circle 10 of FIG. 8.
The evenly-dashed broken lines depict portions of the portable computer that form no part of the claimed design. The dot-dash broken lines encircling portions of the portable computer in FIGS. 1 and 8 and illustrated in enlarged views in FIGS. 9 and 10 form no part of the claimed design.