Pretty much what lyzmorato said , except its taken me ages to type it :)
Are you using XP or Vista ? NTLDR missing means when your pc/laptophas started up it has tried to do the NTLDR check which basically looksat the hard drive on your computer and just confirms its o.k
THere can be a number of causes for a missing ntldr
1. Computer is booting from a non-bootable source.
2. Computer hard disk drive is not properly setup in BIOS.
3. Corrupt NTLDR and/or NTDETECT.COM file.
4. Misconfiguration with the boot.ini file.
5. Attempting to upgrade from a Windows 95, 98, or ME computer that is using FAT32.
6. New hard disk drive being added.
7. Corrupt boot sector / master boot record.
8. Seriously corrupted version of Windows 2000 or Windows XP.
9. Loose or Faulty IDE/EIDE hard disk drive cable.
Ideally you should go through all these options , but if you have alaptop it can be difficult to take a part and check all the connections.
If you are not really computer literate I suggest you get someone whois to follow this guide, of seek help from a technician as this can bea little tricky. This is quite a long one!
When I had this message coming up on my pc it turned out that my harddrive was toast , so prepare yourself for that in a worst casescenario. You may want to remove your HD and back it up now if youdon't want to risk losing any data
Have you made any major changes , recently changed operating system or installed new software? Am assuming you are using XP
Hopefully your hard drive is not broken, and somehow these file havebeen deleted or corrupted, First things first, make sure you haven'tleft a cd or 3.5" disk in your machine that it might be trying to bootfrom
ONce you have made sure there is nothing inserted in the machine , youare going to need to access the bios settings on your machine,
Watch your pc as it boots up at the start , it should give you anoption to press a key to enter bios settings , press this key(sometimes its F2)
Within the BIOS menu, there should be a section that deals with theboot order of your pc , you need to change it so it boots from yourcd-rom first (if you dont understand what i mean by this check thislink
http://pcsupport.about.com/od/fixtheproblem/ss/bootorderchange.htm)
Remember to note down the drive letter of your cd-rom drive as you will need this later mine for example is D:
After you have done this stick in the Windows setup cd and restart your pc
When the welcome screen comes up press R on your keyboard to enter the recovery console
It may ask for an administrator password, if you haven't changed it just press enter
then type in these commands
COPY X:i386NTLDR C:
COPY X:i386NTDETECT.COM C:
Where the X is you need to substitute that letter for your cd driveletter so as I said earlier mine was D: , so on my pc it would read
COPY D:i386NTLDR C:
COPY D:i386NTDETECT.COM C:
(the c: represents your hard drive if it is different from c: you need to change it to whatever it is )
then take out the CD ROM and type exit
then restart
your pc. If this doesn't work you can always formatt your HD andre-install windows, I did this and it worked for about a daybutbecause my hard drive was corrupted the ntldr messga returned and Ieventually had to resort to buying another HD which sorted the problemfor me