A question: Where were you accessing them from?
In the Windows XP "Start" menu, there are two columns. The column on the left has a top and bottom section. The bottom section, which is the default, is a "recent history" kind of start menu, and reflects programs recently used. If you've been using that to start Spider and Paint, but you've been using some other programs lately, it's possible that they've "moved down" the list until they dropped off.
Try "Start," "All Programs," then "Games." If Spider Solitaire is there, try starting it from there. It if works, great; try the same thing for Paint (looking at "Start," "All Programs," then "Accessories"; alternatively, "Start," "Run," and type in "mspaint"). If this works for you, the final thing I'd suggest is: Remember the top and bottom sections of the left column of the Start menu? Drag the icon for the programs you always want access to, to the top section of that column. That's the "permanent" section.
If the programs don't work, then they've been deleted. In which case, I'd surmise that someone accidentally deleted them, or something else deleted them for me. I'd update my antivirus program, and then do a full scan of my computer, followed by an update and full scan of my anti-spyware program. Then I'd attempt a "recovery" using either the roll-back feature of XP if you have it turned on, or using the recovery disk that should have come with the computer.
