To me it sounds like you don't have authority in the company to push these changes. I'm an IT manager and when these kinds of requests come in they have to be approved by a CXO, VP, or some other senior executive, that is the decision maker for that area of the company. Otherwise how do I know that this new program or this new website is in line with the company's goals and direction? You should take your case higher up and get the right people to support your project/request. Also, sometimes the person requesting something is trying to solve a problem but they're requesting the wrong tool for the job or they're overlooking an existing tool. Here are a few examples:
I got a request a couple weeks ago from a VP to change our AV gateway servers from Trend Micro to Norton. And I said no. Reason #1 - IT decides what AV to use, that's why you pay them to make these kinds of decisions. Reason #2 - changing the AV software on all of our gateways would cost money for licenses and time deployment so we can't just change it willy nilly.
I got a request from a manager for Blackberrys for all of his staff. I said no because corporate policy doesn't allow that. The people who run the company decided that it's a waste of money to give each employee a Blackberry. It's not even my decision.
I got a request from a manager wanting Photoshop for all of her staff. I said no because our business has absolutely nothing to do with creating graphics or touching up pictures. I asked her what problem she's trying to solve and she said they need to resize pictures sometimes. All of our computers have Paint.NET installed so I just sent someone for their local helpdesk to round them up in a boardroom and give a quick demo of using Paint.NET to accomplish what they needed. Everybody wins.