Back up your registry before you try this hacks.
1. To change the name of the registered user or company, browse to HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\CurrentVersion and look for RegisteredOwner and RegisteredOrganization. Double click on them and change the values
2.If you have a sufficiently powerful machine and love the animations in Vista, you might want to slow them down a bit. Navigate to HKEY_CURRENT_USER\Software\ Microsoft\Windows\DWM. Once there, create a new key by right clicking on the space below existing keys and choose New > DWORD (32 bit) Value. Call it AnimationShiftKey and enter the value as 1. After rebooting the machine, whenever you want to slow down the animations, press the [Shift] key before it starts.
3. Encrypting and decrypting files in Vista is a multi-click process which takes a fair bit of navigating. With a registry hack, this task can be done with a simple right-click. Navigate to HKEY_CURRENT_USER/Software/ Microsoft/Windows/CurrentVe rsion/Explorer/Advanced and create a new 32-bit DWORD. Call it EncryptionValue and use the value as 1 there. After the system is restarted, you can get encrypting with just a right-click.
4.Speeding up Flip3D: Eye candy is well and good, but not all of us have top of- the-line graphic cards to render all the slick effects. This hack will limit the number of windows that are rendered in 3D, which will hopefully let you have your cake and eat it too. Navigate to HKEY_CURRENT_USER\Software\ Microsoft\Windows\DWM and create a new DWORD value called Max3DWindows. The value should be set to a number between 4 and 9: higher the number the more muscle your graphics card needs to pack. Try it out with different number values by opening multiple windows and checking out the difference.