Expand Windows xp c drive space

The company purchased a notebook a few days ago. I don't want to spend more money on brand names. As a result, I spent 5500 + 295 (memory) on a Lenovo ThinkPad r60e t2300e.
The usage of this notebook is generally okay. Although ThinkPad is low-end, the workmanship is slightly rough, the machine is heavy, but the speed is still good, the keyboard is very easy to use, the heat dissipation and mute effect is very good!
The hard disk is too small because it costs so much. Only 80 GB. I am so worried that I have reserved 15 GB of space for drive C, but I haven't installed anything yet (it's a genuine system that comes with this book, and there are some software in it; I cannot choose the path when I install vs on my own, C # has to be attached to drive C.) in less than two days, drive C has more than 4G. Who occupies the space?
Delete i386 under drive C. Transfer the systools to the edisk, but it only gets 1 GB.
The next day, I found that only 3.87g is left! Quickly clear the temp directory in drive C and the temp directory in the Windows directory, and there are no hundreds of megabytes of files. Transfers the virtual memory of drive C to drive D. Restart the instance, and no new available space is found.
Later, I suddenly restored all the hard drive systems. After the restart, I found that: 8.18 GB! Normal. If you want to get more storage space, do not enable the useless system restoration.