Remove username suggest function in Skype 4.2, Windows Vista?

My dad currently uses one of my old machines for chat and email and such and most recently, Skype. However, there are a bunch of old suggested screennames belonging to other people who may have used my machine from time to time and I don't want my father to see these for a number of reasons.

Is there anyway to make Skype 'forget' who has logged in before? I have tried uninstalling and reinstalling it, but it doesn't make a difference.

Here's a guide by Skype itself on completely uninstalling Skype

Save your personal information (if required). Your contacts, purchases and account information are stored on our servers, but other personal files such as chat messages, voicemail and snapshots taken during video calls, are only saved on your computer. To keep this personal information, you need to make a copy of it.

• Vista and 7: Click Start, type run and press Enter.
• XP: Click Start and then Run...
• Type %appdata%\skype and click OK.
• Copy the Pictures folder and the folder with your Skype name to another location, such as your desktop.

Uninstall Skype.

• Vista and 7: Click Start, type run and press Enter.
• XP: Click Start and then Run...
• Type appwiz.cpl and click OK.
• Select Skype from the list, right-click and select Remove or Uninstall.

Delete the Skype application folder.

• Vista and 7: Click Start, type run and press Enter.
• XP: Click Start and then Run...
• Type %appdata% and click OK.
• Delete the Skype folder.
• Ensure that the Skype program folder has been deleted.
• Go to C:\Program Files
• Delete the Skype folder and the SkypePM folder (if present).

Delete any Skype entries from the Registry.

• Vista and 7: Click Start, type run and press Enter.
• XP: Click Start and then Run...
• Type regedit and click OK.
• In the Edit menu, click Find.
• Search for the keyword Skype.
• Use right-click to delete all the search results (there can be up to 50).

If you want to just remove the usernames and leave Skype on your system, just delete the profile from your computer and it should no longer suggest the username at login.

You should find a path similar to the following:

C:\Users\[username]\AppData\Roaming\Skype

That path should show folders such as Content, My Skpe Received Files and Wallpapers among others.

Just look for the username folder in that and delete it. Restart Skype and you should now no longer have the recently deleted username suggested.