The ornamental design for a tabletcomputerstand, as shown and described.
FIG. 1 is a front perspective view of a tablet computer stand showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a left 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 rear perspective view thereof.
FIGS. 1-8 include surface shadings. The different surface shadings (line shading and stippled shading) in FIGS. 1-8 are used to indicate contrasting materials.