Have you tried looking at Adobe's own website for the tech specs for CS5.5? They are listed quite plainly and very easy to find. Sorry I mean no offense but it would have taken less time for you to google the answer yourself than it would for you to post the question here and have someone else google it for you!
Microsoft® Windows® XP with Service Pack 3; Windows Vista® Home Premium, Business, Ultimate, or Enterprise with Service Pack 2; or Windows 7; 64-bit edition of Windows Vista or Windows 7 required for Adobe Premiere Pro, After Effects, and the Subscription Edition of Master Collection