Reinstall Vista Default Fonts?

Last week I formatted my Windows XP desktop computer and id a fresh clean Vista installation. System worked fine for a week now but today morning when I booted up the computer I found that all my system fonts are changed to either Bold or Italic. I tried restarting the system but it helped. I went to the Vista Fonts folder and found that regular Arial and Times New Roman fonts are missing. Rest all fonts are still there but the two fonts which are used mostly are missing.

Can anyone please tell me if these fonts can be restored back using the Vista DVD? Or if it is available for download somewhere? Do I need to re-install Vista? Somebody please help me out. Many thanks.

As you said the problem started today morning itself, i will suggest you to better try to restore your system to an earlier restore point where the fonts were working. This should probably fix the problem without any problem. In case if that doesn't helps then follow the troubleshooting steps provided here.