The ornamental design for a windshieldstand, as shown and described.
FIG. 1 is a perspective view of the windshield stand.
FIG. 2 is a perspective view of the windshield stand shown in a position of use, with an unclaimed windshield shown in broken lines and forming no part of the claimed design.
FIG. 3 is a front view of the windshield stand.
FIG. 4 is a right side view of the windshield stand.
FIG. 5 is a bottom view of the windshield stand.
FIG. 6 is a left side view of the windshield stand.
FIG. 7 is a back view of the windshield stand; and,