The default directory created in Windows for QuickBooks to store company files is located at:
Windows Vista, 7 and 8 : C:\Users\Public\Public Documents\Intuit\QuickBooks\Company Files
Windows XP: C:\Documents and Settings\All Users\(Shared) Documents\Intuit\QuickBooks\Company Files
Company files may be saved in any location the user has appropriate rights to, however, there is no way to change the original default directory in QuickBooks. Quickbooks will automatically open to the last used directory when opening new company files or restoring backup files.
If this information does not answer your question, you can read discussions and post messages and questions relating to your issue on the Intuit QuickBooks Community site for free. You can contact an agent for additional guidance. Fees may apply.