Help! Need advice on how to upgrade to Windows 7 from Windows 7 Evaluation Copy: Build 7100

[RSFried]

I am on an HP Pavillion Media Center m8200m PC.  The computer came with Vista on it and did not come with any Vista operating system installation discs when I bought it.  I did make a set of two system recovery discs from this original Vista operating system,  About 3 months ago, I decided to put on an evaluation copy of Windows 7 (Build 7100).  In order to do this, I had to remove Vista completely from my computer and then install the the Windows 7 evaluation download from Microsoft.  It has worked fine since, but will expire shortly.  I now want to put on a permanent installation of Windows 7, but am unsure how to do this.  Can someone please explain the procedure to me.  I have read that I cannot upgrade to anything directly from the Windows 7 evaluation copy.  Do I need to recover the computer and install Vista from the recovery discs  (providing I can reinstall Vista from these recovery discs), then upgrade to a permanent version of Windows 7 (from a less expensive Windows 7 upgrade).  Or, will I have to buy a full version of Windows 7 and start from scratch?  Also, is there a way to retain all my data on this computer during this new installation of Windows 7, or will I lose averything including programs, data, etc. and have to reinstall it once I have the new permanent operating system on the computer?  

I'm usually pretty good with this stuff, but can't seem to get a straight answer.  I want to do this as soon as possible, so would greatly appreciate a straight, clear explanation of what to do.  I would truly appreciate it.

[DexterM]

You'll need to do a clean install. You can upgrade the RC to the production version.

[Bob_Headrick]

It is possible to upgrade the evaluation version to the RTM version with some fiddling as shown here.  It would be better to do a clean install.