Access is denied for shared folder

Hi,
We have a shared folder in our network, wherein we store files for quick reference and updating.
I recently installed Norton Antivirus on my laptop that is running on Windows 7. After installation, for reasons that I cannot comprehend, all sharing settings were removed. It took me a while before I was able to share and connect to the printer, but as for the shared folder, it is still not accessible.
I checked all the settings and permissions and as per my judgment, all is well. Firewall is also not an issue in this case because I already checked it. If the printer is able to be shared, why am I having problem connecting to the folder?
Thanks.
