1) You cared enough to mention WinXP and an IDE. Why bring this up, unless you realize there are alternatives. If it really bothers you that much, delete WinXP and your IDE, and jump into the deep end; install $BetterOS and learn $BetterEditor. (And spend the requisite time setting up $BetterEditor to do code-completion.)
Realize that it also doesn't really matter, as long as your code is good, you can code on Win98 for all I care.
2) In my mind, smart is worth zero. Motivation is everything. (And I'm telling myself that as much as I'm telling you.)
What are your ideas? Better yet, what are your ideas that you could do overnight? Do one a week! Realize that there's very much a survivor bias - you don't pause to consider the ideas that you never heard of that went anywhere because, well, you never heard of them.
It's frightening and inspirational, but take it as motivation to stop standing still!
3) Well done on a successful posting. You've written a navel-gazing AskHN post that got you 200+ karma. (Read: the community has given you a good amount of karma, a community-based metric of how much something belongs to said community, and it was for your thoughts (as opposed to posting the latest TechCrunch/Wired/Ars/etc post from the rss feed before someone else got to it).)
So you're working on a startup, and, despite your convictions that it's the right thing, the best thing to do, there's will always be an air of uncertainty. An unproven business plan, a failed-before business model, a different pricing structure, a questionably useful product; some question with no right answer. A competitor in a similar market is great! It validates some part of your startup. You should relish competition, from this crowd specifically, because it means YOUR idea is a GOOD one that someone else who isn't you has decided to pursue it in a serious fashion. (That said, leave my customers alone :p )
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Yes, I do get overwhelmed occasionally that others are doing better than I, but that should be motivation to do better, do more. I frequently find myself thinking "Psh, that app is so lame, I could do better in my sleep." To which my retort is "Sure, but what did you do last night? Sleep? ...yeah".
Do the idea that you have floating around, write down what your MVP is, cut that down to a proof of concept that you could finish the engineering essence of in a day and do that. Stop feeling overwhelmed and get to work. Feel guilty for not working as hard as you could on everything, and work harder. While you're working harder, define your own tiny metric of initial success... If only one person visits, if only 1 persons reads this, if only. Be happy with what you have, but work hard to do even better.