Game launcher for The Sims 3
You would benefit from removing the hard-coded strings out of the code. Best to put them in an app.config file or a resource file. The config file has the additional advantage that the strings could be changed by the user without recompiling.

The naming of the methods and properties is not standard for C#. Use Pascal case for public methods and properties with no underbar, e.g.

Sims3.CachePath = configCachePath;
Sims3.ClearCache();


The naming of local variables and private methods uses camel case, e.g.

isClearedTick();