Thank you for your reply,
As you can see in the photo the HD is 465GB but the partition is only 319gb. There is no unallocated space as expected after the shrink next to C partition.
Part of trying to fix I tried running other partition management softwares. I did get a warning message when I tried to run Partition Magic 8 that said there is some kind of a mistake with this partition size but it couldn't repair the problem because of "missing partition letter" and the software crashed.
Every other windows check or defrag runs fine, as if the missing 150gb are not a problem at all.
Thx again