Without the CD/DVD/Installation Media it will be tough to get those games
back. I'm assuming you have Windows XP, so here is some help:
First I'd suggest checking the actual game executable files have been
deleted, and it's not just the shortcuts which are missing from the Start
Menu. The executable files for the games can be found under
C:\WINDOWS\system32\. They will have names as follows:
Hearts - mshearts.exe
Solitaire - sol.exe
Spider Solitaire - spider.exe
Minesweeper - winmine.exe
Freecell - freecell.exe
Games with the "Internet" prefix, if you have them, will be usually located
in C:\Program Files\MSN Gaming Zone\Windows\. Pinball will usually be located
at C:\Program Files\Windows NT\Pinball\PINBALL.EXE.
I'd suggest searching the internet for backups of the executable files if
you don't have them, perhaps they can be found (just be wary of dodgy
software and bad websites).
Otherwise buy Windows again, or borrow a disc from a friend to get the
files. Microsoft provides instructions on installing the games if you do have
a disc at the following URL (Windows XP):
http://support.microsoft.com/kb/307768
Best of luck,
RV