I want my magento website fixed

i changed some url options in the admin panel area of my magento site and ever since then its not working properly, i cannot take orders or access admin panel to rectify this

please help me asap

i have seen people say they did the same and fixed it by doing the following
thanks I fixed it by using the following step:

============Step 1=======================
In phpmyadmin find core_config_data and on its last page deleted the entire fields not just the data in them:
admin/url/use_custom
admin/url/custom
web/secure/base_url
web/unsecure/base_url

==========Step 2=========================
In /public_html/var/cache/ delete all the files:
mage--1 through mage--f

i cant find this so need help