installed programs won't appear on linux lite

I've been struggling to install any program on linux lite. After I install them with Synaptic, the files of the installed program are there, but they don't appear anywhere in the dash (searching in the dash included), as well as in 'open with other application...' context menu. I can't find how to open them in the directory that they're installed in, and I used Synaptic to locate all the paths that the programs are located at, I've got a XMMS launcher, but nothing happens when I double click it. I'm new to Linux and I'm on a 32 bit system, if it makes any difference.