Make sure you have full Admin rights on your machine and there aren't any hard disk or RAM errors listed in your event logs. Typically these problems can be caused by faulty .NET Framework issues or spyware/virus problems.
.NET Framework issues can be resolved using the .NET Framework Cleanup Tool. More information about this tool can be found at my discussion thread here:
FLEXnet License Admin | MSI Cleanup Utility | .NET Framework Cleanup Tool | IPv6 NLM Fix | adskflex.opt Options File | Combine .LIC Files | Disk Space