Or use
PasteScreen!
To use it, save the script as PasteScreen.ahk, and install
AutoHotkey.
Skrommel
;PasteScreen.ahk
; Pastes screen captures into Paintbrush
;Skrommel @2007
#SingleInstance,Force
#NoEnv
#Persistent
SendMode,Input
Return
~*PrintScreen Up::
Run,mspaint.exe,,,pid
WinWait,ahk_pid %pid%
WinActivate,ahk_pid %pid%
WinWaitActive,ahk_pid %pid%
Send,^v
Return