The ornamental design for an all-in-one computer, as shown and described.
FIG. 1 is a perspective view of an all-in-one computer showing our new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view of another aspect of the all-in-one computer, showing parts of the all in one computer folded.
The broken lines shown in the figures form no part of the claimed design and the shade lines in the figures show contour and not surface ornamentation.