Is this a new laptop? I ask because you mention you only got it 3 weeks ago.
If so, I would guess that most of the advice you will receive here would be to contact the makers/suppliers. It is under warranty, and if they have supplied a system that is not working, then they must put it right. Anything we suggest may void the warranty.
I know this is probably not what you want to hear, but with new systems we nearly always get the suppliers to fix them.
this is the second problem ive had with this laptop since i got it like 3 weeks ago. when i boot my hp netbook it shows me that it is missing the file <windows root\system32\ntoskrnl.exe. i am reading forum after forum on other sites about this and they say to boot through a recovery system on my windows disk. but thats the problem i dont have my disk. im only 14 years old and obviously not experienced. if you need any more information just ask me. please reply with a simple easy solution for this problem as soon as possible.