I was considering an overheating problem, but given it works fine in Safe Mode and how long MBAM was running for, other problems could have manifest.
However, download the free version of HWMonitor to see what the temps are like.
http://www.cpuid.com/softwares/hwmonitor.htmlThe freebie link is down on the left.
EDIT - What about running a chkdsk /f from the Recovery Environment ?
Tap F8 (usually) as you switch on and select Repair your Computer - change/confirm keyboard/currency etc. and navigate to the RE and select Command Prompt.
Enter bcdedit |find "osdevice" and using whichever partition letter, enter chkdsk x: /f where x is the partition letter.
That is the Pipe symbol before find which I usually explain is the uppercase of \
No reboot is required because this is done outside of Windows and it's report will be in the cmd window.
You could also use the green download button to download the trial version of HD Sentinel which will give a written report on the status of your HDD.
http://www.hdsentinel.com/