I JUST INSTALLED VERSION 2.10.413. NOW I HAVE NO SCREEN SAVER "WINDOWS CAN NOT START THIS SCREEN SAVER". THIS IS TRUE FOR ANY SCREEN SAVER. I AM RUNNING VISTA HOME EDITION. I LOVE THIS PRODUCT AND HAVE NEVER ENCOUNTERED A PROBLEM BEFORE......
Please do not type in all caps, it makes reading what you wrote more difficult than need be and is considered shouting.
What you could try is using a System Restore Point to recovery your system to an earlier time - if you have a recent Restore Point.
Installing defraggler, alone, would not have made any difference for screensaver
Did run Run a Defrag using the program?
Operating System version? sorry it was hidden by the use of CAPS LOCK, thus the reason not to use caps