I would contact the local Solidworks rep. for support (if you have the maintenance paid).
Otherwise I would uninstall again, clear the register from solidworks (uninstall does not remove the keys and values in the register). Google abit for uninstalln clean solidworks etc to get more information.
What did you do when it went down? Changed drivers, settings, just modelling?
Along with Daniel's suggestion in regards to deleting in the Registier I would use Microsoft Fixit Install Uninstall
It will show if SolidWorks has "fully" unistalled
Did you manage to get it start again?