Last night, right before sleeping, I left my hard drive to be defragged. When I wake up, it was still checking for errors on the hard drive. And it was at 2%, after which it would start at 0% again.

I decided to check for errors (solely) and found out that it couldn't complete the error check because a certain process was writing to the hard drive. A Lot!

Using filemon, I found out that the name of the process was Kernel32 and it was writing to a file named win386.swp

What is win386.swp and why wasn't it there before?
Any solutions?