You can delete the question from CP by going to it's page from the Questions link in your profile:
Member questions & answers - CodeProject[
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Once the question is opened, hover your mouse over the question body, and a few options will appear in the bottom right.
Click on the Big Red X and it will ask you to confirm.
But...firstly, I'd ask you not to if anyone has answered - people have put some considerable effort into helping you: it's rude and selfish to throw that away, it's saying "I got what I wanted, I don't care about you". It's also unhelpful to the community at large - someone with a very similar problem won't be able to see the answers that helped you.
And secondly, that doesn't remove it from existence: Google, Bing, and other engines maintain a cache of pages for some considerable time, so the question will probably be "visible" for a long time.