Where are the "Program Files"
 

What is the linux equlivelant of "C:/Program Files"

in general /usr

Most of the time /usr/bin or /bin.
Good luck.

Windows usually puts a lot of stuff under "Program Files". Executables, configuration files, help files, etc. These are usually more spread out in Linux, based on the function of the file. Executables are typically found in some "bin" directory. Be that /bin, /usr/bin, /usr/local/bin, /sbin, /usr/sbin, etc. Configuration files are often found under /etc, but they could be other places. "help files" might be found under /usr/share/doc. "man pages" (another type of "help file") under /usr/share/man. These directories are generally set at compile time or via environmental variables, but can usually be overridden at runtime.

http://www.pathname.com/fhs/

The Filesystem Hierarchy Standard has been adopted by most Linux distributions. Those that haven't usually have a fairly similar filesystem layout. This will tell you where to look for most things.

Linux

/bin

linux base utilities

/boot

boot loader, kernel, initrd, and various other boot files

/dev

special device files, either character device or block device

/etc

system configuration files

/home

user stuff

/lib

linux core libraries, symlink to kernel modules

/media

mount points for removable drives

/mnt

mount points for whatever you want

/opt

some distros pack /opt full of everything, other don't put anything there. /opt is like /usr

/proc

virtual file system of processes. These files aren't taking up disk space.

/root

/home for root user

/sbin

sysadmin utilities for root user

/srv

root directory for ftp and web servers

/sys

very low level hardware module state info

/tmp

temp files

/usr

user programs, libraries, documentation, and a load of other goodies.

/var

log files and stuff you usually don't use often, but look around.


If you need to find a file:
su
root password
updatedb --prunepaths='/tmp /usr/tmp /var/tmp /dev /proc /sys'
locate myfile

You only have to do updatedb once. locate works after that.