I used commands like dir/ah on cmd. All the hidden folders got listed. i ran command attrib foldername -r-a-s-h. I am getting access denied on folder. Like access denied on D:/maks.
I'd recommend you to attempt accessing/seeing your files using this tutorial: http://www.wikihow.com/Unhide-Folders-in-Windows-7
If it still doesn't work, I'd suggest you to go to Disk Management and see how your internal HDD is listed there and if there's anything unusual in its volume/partition status.
Hope this helps. Keep me posted!
Cheers,
SuperSoph_WD