I have tried to get the 1.6.1 IDE to run, the splash screen appears for a brief moment then disappears.
My current version 1.6.0 runs fine and I also tried the arduino-nightly 1.6.2 which also runs okay.
I re-downloaded 1.6.1 in the zip and the installer formats both act in the same way.
I’m running Windows 7 Home Premium 64 bit.
I normally install manually using the zip file, and today was the first time that I tried the installer.
I have temporally moved back to 1.6.0.