Changing Theme:
First off, you will need to download a theme folder and dll. The one I use is this.
View that page and click download. When it's finished, it will be in a ".rar" file. Now extract those files into "C:WINDOWSResourcesThemes."
Leave that RAR aside now, we won't be using it anymore. You can delete it if you want.Now, we need to download a patcher for the dll that runs your themes. Since you can't use your new theme yet, you need to download this patcher.Go to this link and click on the download button. Then download one of the 2 links in the next window. It shouldn't take long (only 1 MB). When you've finished, it will be in a ".rar" file. Open it and click on the EXE.
A new screen will pop up.It will look likethis.
It will ask if you have Windows Service Pack 2. Just Click "yes", it won't matter. Then when you finish patching, it will tell you to restart your computer. Restart it. Then log into your user and right click on the desktop(not any icon, the background).
Then click "properties."
Then click the "appearance" tab and select the new theme in windows and buttons
Congratulations, you're done with themes!
Changing Mouse Cursor
You can download the mouse cursor pack at this link.
Now the thing that you downloaded will be in a ".rar" file. You must extract it. Extract it to a random folder, doesn't matter which. Now in the folder that you extracted it to, there will be a little notepad-ish file called "install.inf". Double click on it and it should install automatically.
Now after installing, go to Control Panel > Mouse. A new window will pop up. Click on "Pointers" tab.
Congratulations, you can now use the mouse cursors from Vista!
Changing Sidebar
For those who don't know what a sidebar/widget is - this is an example of one.
To download a sidebar installer, go to this site: http://www.thoosje.com/It will make your XP look like Vista for sure.
There are many options you can choose from to appear in your sidebar.
Congratulations on making your computer look like Vista!
