Unable to install Website X5 Evolution 9 on my PC.

My operating system is Windows Vista, my processor is Intel Pentium Dual CPU E2140 1.6GHz, 2GB RAM,  and I believe I have the required supporting elements (Adobe Reader, Net Framework 3.5 etc) I have tried three times to install it but without success. It continues to say "error - try again". Any advice please?

PS: I'm not the most computer savvy of people I'm afraid.