In earlier beta testing days of Windows 7, it was possible to remove the "Blur" effect from window borders (window titlebar, etc) but the functionality was removed in later builds. Even the RTM build doesn't contain this functionality.
We just needed to alter a DWORD value in Registry Editor and the Blur could be removed.
No need to get sad. "PacMani" @ DA has created a small batch script which replaces 2 RTM system files with the beta ones and also incorporates the required registry DWORD values automatically. So you can get the good old Beta functionality back in RTM build.
Simply download the ZIP file using following link:
UPDATE: It seems the software has been removed by the developer.
How To Instructions:
1. Extract downloaded ZIP file and run "Patch Blur x86.bat" file. If you are using x64 bit version, run "Patch Blur x64.bat" file.
2. It'll take a few seconds and you'll see window without blur.
3. If you want to put the blur back, run "Enable Blur.bat" file. And if again you decide to remove the blur, run "Disable Blur.bat" file.
4. Although you would not need to run "Unpatch Blur.bat" ever, but in case you want to restore the default system files back, run it.