DESKTOP WINDOWS MANAGER EXE FILE

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft® Windows Vista™ Home Premium, Service Pack 2, 64 bit
Processor: AMD Phenom(tm) 8400 Triple-Core Processor, AMD64 Family 16 Model 2 Stepping 2
Processor Count: 3
RAM: 3837 Mb
Graphics Card: NVIDIA GeForce 9200, 256 Mb
Hard Drives: C: Total - 141943 MB, Free - 37292 MB; D: Total - 305242 MB, Free - 22982 MB; E: Total - 144353 MB, Free - 139378 MB;
Motherboard: Acer, WMCP78M
Antivirus: Norton AntiVirus, Updated and Enabled

 

Hello. Every time I boot my pc up I get this error box.-- Could not load or run C:\users\admin\appdata\local\temp\dwm.exe' specified in the registry. Make sure the file exists on your computer or remove the reference to it in the registry. -- I just get rid of the error box and the pc boots up. I have to do this everyday. I've been told the exe file would never be in that location. Somehow my Desktop Windows Manager got wiped off my computer. I can't find the dwm.exe file anywhere. I did a full system scan and nothing came up. I installed HijackThis, but when I right click on it I don't get the Run as Administrator option. Why can't Norton identify and solve this problem?  Thanks