What ho one and all,

Should be preparing for Santa's arrival, but I am posting this question instead!

Running XP sp3 (still); every few months, I clean the HDD with a few utilities, scan for any virus / malware etc and defrag C: which is a 100gb partition. Generally, around 50 gb is in use; the largest files are a VM, AutoCAD and probably Photoshop.

After a recent defrag, I was amazed that I only had 25% free. Using Space sniffer, I found six, recently created (last few months) files ranging in size form 500kb to 6gb. Typical file name was A2F66F1B127C0036C4539DB3AF7E20D1F0548574 with no extension.

I have deleted them, back to around 45% free space and no adverse affect.

What could these be? How and why were they created?

Grateful for any suggestions.