MFT must refer to the Master File Table. If this is corrupt you may have quite a problem as this is in effect an index of all the files and folders on your drive. If it's gone wrong the system will have problems finding files etc. I assume you can get into Windows so to run checkdisc right click on the drive and choose properties. Click the tools tab and click Check Now under Error-checking. I would not advise defragging until the mft is fixed, as defragging actually works in reverse with the mft as it cannot move the first fragment. You already damaged mft will then also be fragmented, possibly adding to the problem.
If checkdisk fails to run, and it could take some hours to complete depending on the size of the drive, it can be run from the Recovery Console. If you need help with this post back.
Thanks for the very useful information. The chkdsk operation took only ten minutes and I was able to see that it deleted 6 files. The rest went so fast at the end that I was not sure what it did. It looked like some interesting info as it flashed on the screen before it went into a restart. When I said I couldn't defrag I should have said I couldn't do the analyze part before the defrag so I didn't continue. Analyze now works so I assume defrag does but I will leave it a day or two.
Now I understand chk dsk and where it is.
I still have some problems with restore etc but hey we all have to have some probbies don't we?
Did you tick the two options when you started Checkdisk? It's totally optional, but if you do, it will perform a more thorough check/repair. First, it tells you it cannot run now and asks if it can run at the next boot-up; click Yes and it will run before Windows loads.