HI,
Try: C:\Windows\system32\dllcache\mspaint.exe
Maybe you had uninstalled it, if you want it back in your menus, and system32, try:
Start > control panel > add /remove programs > add or remove windows programs (on the left)
A new window will be opened:
Select accessories and click "details..." > acessories and "Details..." again > select "paint" if it's not already.
Not sure it will work, but anyway, you can use many other programs to take screenshots.
Vous avez beaucoup d'avenir derrière vous. :-(