The drive size and partitions are is often found when you look at the drive management tool in Vista. Be sure you look there. Your drive c was created by someone that set it to 32GB.
As to what is creating files behind your back there are too many to list here but read this forum's top post at http://forums.cnet.com/7723-12546_102-238817.html?tag=threadListing;forum-threads and specifically post number 14.
Bob
Okay, I have an eMachines computer with Windows Vista Ultimate. I have a 120GB hard drive (I have taken a look at the hard drive itself to confirm this), but in the My Computer window, it's reading that I have only a 31.4GB hard drive, and I only have 0.97GB of free space left. I only have a total of 3 songs downloaded, and about 5 documents in wordpad, but they are only KB in size. Everything that I have downloaded should not equal to what it does. Plus, I have over half of my hard drive space missing! What on earth is going on here?? How can I fix this?? Please, help! Any advice anyone can give me is greatly appreciated! I don't know what to do! Every day I run Disk Cleanup and CCleaner, and it frees up only MB in space, and on top of that, the space I have left will randomly decrease without me even downloading anything! Yesterday I had about 1.74GB of free space, today I only have 0.97, and some days I'll only have merely MB of space left! And I downloaded nothing! Please, please help! What do I do??
Thank you!

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