Guys out there,please help me. My middle-C note is defective, it doesn't sound good, air spurting somewhere around the hole, it can't properly covered to produce melodic Middle-C note. How can i repair this?

Just out of curiosity...is it an actual middle C (below the staff) or is it one of 'our' middle c's...therefor on the staff or above it? Just want to clairify for answers.

As Lera suggested, you should probably take your flute to a tech. If this is a relatively new development, and you haven't had issues with your middle C (regardless of what octave you mean), the chances are that the issue is flute related, and unless you have the proper training and tools, you should not attempt to fix it yourself. If you can, try playing the note on a different flute that you know is in good working order to be sure whether or not the issue lies with you or with the instrument.

i would also like to add that low c (c below the staff) is pretty hard to play anyway

On a flute that's in good shape and is of decent quality, Low C shouldn't be particularly difficult to play. It can be difficult to produce notes in the lowest range with the same volume and projection of other pitches, but simply producing a Low C shouldn't pose much of a problem. If you have leaks anywhere in the instrument, then you may experience difficulty.

Even with a well adjusted good brand flute, I do think that low C is one of the harder notes to produce especially for a beginner such as Liegh. I don't know about you but I have been playing for around 20 years and I don't think that note is particularly easy all the time.

the C note that you have to cover all the holes, that one,air spurting sideways because of leaks,and it does not sound good, or C note wont produce...

also the brand of my flute is Parrot, i think some of you guys out there is not quite familiar with this brand, i prefer this first for my lesson, and i'm mastered flute instrument i probably shift to other brand, like Yamaha..(hoping someday)..

just keep practising and keep at it, then for grade exams find someone whos got an old begginer flute you can borrow, but its quite hard to get a low c any way i have only just managed to play it (you could just have a leaking pad take your flute to a expert and ask them if its you or a leaky pad, or if the flute has a big leak

Some flutes are just plain hard to get a C on. My original student model Gemienhardt in Jr High was impossible. A swapped in B foot solved the problem. B was now impossible, but C was no problem. Go figure.

Nah, it was a piece of crud $300 flute (not even as good as the current 2 series). My Yamaha was a snap to get any note I wanted by comparison - easily half the effort and twice the tonal stability. Almost like playing on autopilot by comparison. Later, in college, I learned to do instrument repair and even properly adjusted, it was junk. No point in selling it - what - it's worth $30-$50? It's worth that much for nostalgia. Every so often I still play it as it's a good "beater"
to take places where I don't care what happens to it. (kind of like the $100 guitar you take on camping trips)

The fact that it was well adjusted does not mean the pads were all seated and sealing properly. I have to agree with Micron....There most likely were (and probably still are) some leaks, or your playing wasn't up to par at that point. If swapping footjoints fixed the problem, odds are the pads on the footjoint were leaking, or the tenon wasn't fitted to the receiver correctly.

thank you so much guys, ya'll contributed opinion how to fixed it...i have to think of it which do i prefer..but all you guys are great...thanks for helping...keep up the good work...lets all have fun...God Bless Us All....Long live Musicians...