I have been using Solidworks 2015 SP0 for a few months now with no problems. I changed my monitors and now it hangs during start up on the splash screen. The splash screen reads 'Verifying Licence'. I have re-installed the software and even tried different monitors. I can't see how changing monitor should cause this.
I don't think that's caused by you changing monitors. I've gotten a similar message when trying to open a new SW version because our IT people needed to perform some magical process on our network server so it would work with the latest SW release. If you're also working on a network you may have a similar issue. I'd suggest you contact your VAR (Value Added Reseller, the people you bought SW from) for help.