Can't help you with your problem directly, but I hate when people use the reset button. So, I just had to check.

1. Did you try opening a new virtual console with <Ctrl><Alt>+F2 (or F3 through F6), and attempt to kill LimeWire manually?

2. Did you try <Ctrl><Alt>+<Backspace> to try to shut down your X-server?

3. Did you attempt a somewhat graceful shutdown with the SysReq sequence? (SysRq might be labled Print Screen on your keyboard).. You can get details on what everything does elsewhere, but write down RSEIUB somewhere, then when you lock up hold down <Alt>+<SysRq> and press those keys <Alt><SysRq>+R, <Alt><SysReq>+S, <Alt><SysRq>+E, etc. in the order show. These are low-level calls that will try to close all your files, sync disks, and so forth.