[davidson]

I checked the hotscrips.com and found few fee helpdesk. If you are using any, please share with me.

[Linux]

Cerberus provide free helpdesk with limited features. You might have a look into them

Cerberus Helpdesk .::. by WebGroup Media, LLC -- Helpdesk, Email Management, Trouble Ticket System, Customer Relationship Management

[flex9]

If you are looking for Live Support also, LiveZilla is the best free options there is in my opinion. Not sure about a free fully featured helpdesk solution.

[Alexandre]

perldesk is not bad as well.
I like ProSupport

[Furro]

Hi, I think Radmin is an excellent helpdesk software. But it is not free.

[webhostfreak]

Hi,

I would suggest spending your money for a more reliable and get suitable help desk rather than going for cheap/free unreliable software.

I would recommend Kayako, WHMCS etc...

[intellitech]

There are some excellent open-source helpdesk systems out there, it would primarily depend on your own organisation, how your support staff operate, and I guess, if there are any specific of custom features that you may need / require - however, one that I would recommend is perhaps - ACCORD5 — Trellis Desk

[copxxx]

osTicket is the best free and open source support ticket script - osticket.com

osTicket is a widely-used open source support ticket system. It seamlessly integrates inquiries created via email, phone and web-based forms into a simple easy-to-use multi-user web interface. Manage, organize and archive all your support requests and responses in one place while providing your customers with accountability and responsiveness they deserve.

[Alexandre]

I agree, osTicket is not bad