I reported about the problems with not installing and missing content back on the 15th April - David Light has posted about it on his blog on the 10th May, however his process was for Windows 7.
For Windows XP
1. Open the Windows Control Panel > Add or Remove Programs.
2. Highlight your 2012 Revit product and choose Change/Remove
3. In the subsequent Revit dialog, choose Add or Remove Features.
4. In the Select Content section, choose US Metric.
IMPORTANT - Make sure that you keep the United Kingdom ticked because if you don't it will remove all your UK Content so you end up with the missing templates but you will have lost all of your UK families.
How do I know this, because I didn't and after 15-20 minutes I had lost my UK Content.
5. Click Next to install the content.
We the UK users should not have to install USA content, and this does not address the missing European Specific content that is also missing see my review document click HERE to download
Autodesk - what you should have done was fixed the problem and not have recommended a bodge. The UK Library should have been fixed and a download made available.