In what location or folder in my computer hard drive are my bookmarks stored.
Your Firefox bookmarks are stored in a database file (places.sqlite) in your personal settings folder (your Firefox profile folder).
The easiest way to locate your personal settings folder is from within Firefox:
Help > Troubleshooting Information > "Show Folder" button
Are you asking for a particular reason? Maybe: Restore bookmarks from backup or move them to another computer
Windows XP: C:\Documents and Settings\yourusername\Application Data\Mozilla\Firefox\Profiles\xxxxxxxx.default\bookmarkbackups
where yourusername is the user name you logon to winxp with, and
xxxxxxxx is random alphanumerics (there should only be one xxxxxxxx.default file in the location specified).
Windows 7: c:\Users\yourusername\AppData\Roaming\Mozilla\Firefox\Profiles\xxxxxxxx.default\bookmarkbackups
Can't help you with Win8 but imagine it's similar to win7.