It is still probably resident on your PC, it's just that the shortcut has disappeared.
Go to 'Start', then 'Settings', then 'Control Panel'
In the 'Control Panel' go to 'Add or Remove Programs'
In the 'Add or Remove Programs' window click on 'Add/Remove Windows Components' in the left column.
When the 'Windows Component Wizard' opens, highlight the 'Accessories and Utilities' then click details. A new window will open.
Highlight 'Accessories' and then click details.
Be sure that 'ACCESSORIES' & 'GAMES' have a check mark by each one. By HIGHLIGHTING each category above you will be able to see which items are checked or not. Select those items you desire or just check them all if you're not certain. If they do not have check, i.e., check them and click okay. If they do have a check mark, uncheck it then check it again and click okay (this will force it to reload the shortcut again).
Click okay in the next window, and okay in the next, and then 'Next' in the wizard. It will start to load your settings. Click finsihed when it completes. Your Paint, Calc, etc. should be back to where they were originally and function correctly. Sometimes it may require the Operating System disk, so be prepared to have the disk ready if asked to insert it.
This should put your ACCESSORIES (CALCULATOR, PAINT, etc.) and GAMES (Freecell, etc.) back to normal function and availability. They can be easily found and tested by going to START, ALL PROGRAMS, ACCESSORIES and then locating and selecting the desired program.