Digital Certificate Inquiry

Dear members,

I am very new in digital certificates and authentication matters. I created an exe application ( 2 dlls are required to run this application) for my e-learning website. Currently, I found problem in accessing the application from the browser on computers with XP, IE 6.0.2**. ActiveX bugs keep disabling me to run the exe file. However, after I set those ActiveX controls in Internet Options--Security Settings to 'prompt', a message box displaying 'ActiveX control on this page might be unsafe...Yes/No' pop up. If I click Yes, it will run my exe application smoothly. Therefore, I wonder if I digitally sign my application could solve this security problem. I don't think its advisable to request users to set their Internet security setting to medium or lower as this will place the user's computer at a risk.

Another query is that whether can I find any free digital certificates as I have a tight budget for my project. I searched on the net and most of them provide 30 days free trial, which is not sufficient enough for my website. How much is the cost of digital certificates? Looking forward to some reply soon.

Thanks in advance,
Janice