This assumes you are using American English versuion of W-7 Language type 1033
All Windows 7 allows is for you check or un-check play start up sound in Windows 7 you have to do the following to change the default sound of your choice

1) Use the following beta program Reshacker from
Download Resource Hacker 3.5.0.82 Beta / 3.4.0.79 - Analyze, change, add, erase or extract resources in EXE and DLL files - Softpedia

2) Locate the file "imageres.dll" in C:\ Windows\System32 folder. For instance, C:\Windows\System32\imageres.dll. Copy that file into a different location, i.e. your desktop.

3) Download ResHacker .

4) Open ResHacker. Open the imageres.dll file in ResHacker.

5) Find the folder that reads "WAVE" and expand everything below that.

6) Right click 1033 (this could have a different name depending on your locale), and click Replace Resource. Click "Open file with new resource", and find the wave file you want to replace it with. Once you're done, in Resource Type, type "WAVE", in Resource Name type "5080", and under Resource Language type "1033" (or whatever number you have). Once done, click Replace.

7) Click File, then click Save. Now you can copy this file to Vista's System32 folder.

Keep the imageres_original.dll file ResHack left behind in case you want to revert back to the original sound.

8) For Windows 7 go back to C:\Windows\System32 directory rename the imageres.dll to Imageres.old then copy and paste the new hacked Imageres.dll into C:\windows\system32 directory

Now you can use this reshacker instead as I used Windows 8 x32 
http://www.angusj.com/resourcehacker/reshack_setup.exe

you can download take ownership from here - Take Ownership Shortcut

I then took ownership of the imageres.dll in System32 folder, so I could change the extension to .old
That way I was able to copy the new imageres.dll file into that folder.

This worked perfectly for me then

To take ownership of files and folders you can use this Tweak and it will give you the option to take ownership when you right click on a file or folder or drive.


When you use take ownership on a folder, it will take ownership of all the files and sub-folders inside the folder as well.

If you added the Open Command Window Here as Administrator context menu item, then adding Take Ownership will remove and replace it.
DO NOT TAKE OWNERSHIP of the C: (Windows 7) drive!!

Step 1-> download from here 

Step 2-> Open the downloaded zip file, extract (drag and drop) the .reg files to your desktop, then right click on the extracted .reg file you want to use and click on Merge.
NOTE: If you do not see a Merge option when you right click on the REG file, then you will need to check in Default Programs to set the reg file extension to have it's Current Default program set as Registry Editor(C:\Windows\regedit.exe). Afterwards, try merging the REG file again.

Step 3-> Right click on whatever you want to own and and select take ownership, it works and I have used it heaps.