I use a Lenovo G550 with Windows 7 Home edition, a laptop that is ideal for my writing skills. I do not do any gaming, but do make a lot of use of Skype, having family overseas, and of several web design aids. I was most disconcerted a couple of days ago when the laptop announced to me that its C drive was full, and that I should do something about it. Knowing that I had only used somewhat less than a quarter of the disc space led me to doing some investigation, where I found several other instances of the occurrence with other individuals. Liz advised me to check out a youtube video that listed the best ten system applications, which I did.
To isolate the problem I used an application called JdiskReport - you need Java to be running in order to run this program. The program analyzes your hard drive, giving a graphic description of what it contains. I found that almost 200 Gb was taken up by .sst files. Further analysis showed that there were more than a million .sst files in the Google Earth unified_cache_leveldb_leveldb2 directory, all created within a few minutes of each other. You can read about this problem on the GE forum here.
Uninstalling GE will not get rid of the unwanted files, which for me were found in C:\Users\xxxxxx\AppData\LocalLow\Google\GoogleEarth\unified_cache_leveldb_leveldb2 . Substitute your user name for the x's. You'll have to manually delete all of the .sst files. I found the quickest way was to mark them using Ctrl and dragging the pointer over them, hitting delete and then later emptying the Recycle Bin. If you have a program such a Total Commander you can mark all the .sst files and delete them. I later re-installed the latest version of GE , and now have 200 Gb of free space to play with again.(by the way GE know about the problem and are doing their best to fix it, but they need feedback from anyone experiencing it)