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Don't worry about the recovery partition. That is set by the factory and allows you to return your computer to factory specifications so it will be just like the day you brought it home. If you ever have to use the recovery option it would erase everything else on your hard drive (documents, photos, music, other programs, etc) so make sure you've backed up those important personal files or you've made a system image.
The 39MB OEM partition is probably the boot partition. It's what the computer looks for when you first power up the machine (when it first boots.) Again, this is nothing to be concerned about.
Now for the C: partition that's 70% full. The first thing I'd suggest is going through this tutorial. Hard Disk Space - Free Up and Recover
Not everything will apply to you. I'd try the following options: 1 (you could substitute TreeSize free
), 2, 3, 4, 9, 11, 12, 14, 17, 19, and 21. If any of the other options do apply to you feel free to give them a try, too.
Please post back if you were able to get back any hard drive space and how much.