For ePubs you'll need to install Adobe Digital Editions 2.x, register it with an "Adobe ID", and then use it to open the .ascm file. ADE will then download the actual ePub file.
For Kindle you'll need to download for an E-Ink device (which I assume you don't have) OR download using Kindle for PC/Mac.
Once you have an ePub or Kindle book downloaded using ADE 2.x (ePub) or Kindle for PC/Mac (Kindle), you'll need to get calibre and the DRM-removal plugin for calibre. The plugincan be found at Apprentice Alf's blog.
http://apprenticealf.wordpress.com/
But for any more detailed help with DRM removal you'll need to ask elsewhere - e.g. Alf's blog.