This has become very confusing now. Having run CHKDSK on both of my drives, I have found no errors or bad sectors. This computer was set up professionally as a workstation for rendering and doing work with computer graphics in cinema 4D. There was no junk installed, which i'm quite thankful for. Being only about 2 weeks old i've barely had time to install anything on it beyond downloading content for Daz studio, Iclone, Character creator, maya and various other graphics applications. I'm doubtful that malware would be a problem, but I will have a look. A hardware issue does seem to be a good explanation for the collection of different problems I am having, but it doesn't seem like it's a disk problem. In a way, I was hoping that I would find the disk did have an error. I would have a clear path to solution. Now I don't have a clue what was going on.
Corrupt install of Iclone I guess? Not sure what else to think.
Looking at the logs using the event viewer - i'll put the details here (sorry for this info dump)
Checking file system on D:
The type of the file system is NTFS.
Volume label is Memory.
Stage 4: Looking for bad clusters in user file data ...
527088 files processed.
File data verification completed.
Phase duration (User file recovery): 1.22 hours.
Stage 5: Looking for bad, free clusters ...
860139314 free clusters processed.
Free space verification is complete.
Phase duration (Free space recovery): 0.00 milliseconds.
Windows has scanned the file system and found no problems.
No further action is required.
3815429 MB total disk space.
465570432 KB in 467785 files.
126516 KB in 55616 indexes.
0 KB in bad sectors.
746111 KB in use by the system.
65536 KB occupied by the log file.
3359919 MB available on disk.
4096 bytes in each allocation unit.
976750079 total allocation units on disk.
860139315 allocation units available on disk.
Total duration: 1.24 hours (4492633 ms).