Why don't people just tell the truth anymore?
Prospects who've downloaded your software, say they are interested but never, ever buy from you. Do they think they are doing one a favour by not just admitting they are never going to buy? Please. The extra time a salesperson wastes with a tire kicker could be better spent on real potential clients. As a sales rep make sure to limit your time spent on tire kickers as much as possible. Only provide them information on a "quid pro quo" basis. Make frequent use of the phrase "I'll do this for you if you do this for me."
Worse than tire-kickers are those professional purchasers who need "column fodder" for their next large purchase. They begin an entire make-believe sales cycle for the sole purpose of compelling you to spend hours of time preparing an RFP response that you never had a chance at winning in the first place. Some firms require their purchasers to get three bids before being allowed to confirm the order with the company they were going to do business with anyway. Since an RFP is something of value and takes a lot of time to prepare shouldn't software vendors charge a fee for these?
Here's a hint; if you didn't help your prospect put the RFP together chances are you are not going to win. If the prospect hasn't fully evaluated your software technically; chances are you are not going to win. And hey if your prospect needs a quote by the end of the month and today is the fifteenth and this is the first you've heard from them; chances are you are not going to win!