Recommened ROM

First hard spl  with 2.51  http://forum.xda-developers.com/showthread.php?t=520312

Then grab the latest Energy  rom from here http://forum.xda-developers.com/showthread.php?t=562942 snd enjoy.

Not hard at all. I bought my Pure last month and flashed it the day I got it. Easy as pie.

I believe so. I did it through activesync. If hard spl fails install the enablerapinew cab.

Just thought I'd give my 2 cents!  I'm using Energy's latest Sense 2.5 with Cookie's Home Tab and loving it!  It's faster than the stock ROM, Prettier, Battery is better.  I'm a happy guy.  If you are having problems deciding to flash, go for it!  You'll love it.  I recommend the storage card method!

Glad it worked out for you and Greenskeeper! Its a pretty nice ROM.

Shouldn't hurt anything upgrading the SPL with the ROM already installed, but since most ROM updates are based on the most current SPL (2.51) you definitely want to in order to insure stability.

I am assuming you downloaded the update_to_251.zip from http://forum.xda-developers.com/showthread.php?t=520312

Make sure you unzip it in its own folder, I just did mine on the desktop. Should be a file in the folder named CustomRUU.exe or RUU.exe. Connect phone via data cable and select ActivSync. Depending on which Windows version you have, run either ActiveSync (XP, 2000 etc.) or WMDC (Vista and Win7) make sure it Sync's and holds, Vista tends to drop Sync for some reason. Double click the RUU.exe file and it SHOULD take about 30 secs to 2 minutes to complete. When done, do a hard reset, boot it up and then do a soft reset. This is to reset the the SPL properly so the mods take full effect. You will have to re-do any personalizing but it's worth it. To verify the SPL version, turn phone off, hold down the down-vol soft key and tap the power button. It will show the bootloader screen and SHOULD read 2.51 OliNex.

Rename the unzipped file to TOPAIMG.NBH and put it in the root of your storage card. Then reset and go into bootloader. Do a soft reset while holding the "volume down" key on the left side of the device. keep holding the volume down key until you see tricolour screen which is the bootloader mode, then release it. Follow the instructions on screen and you should be fine. That's how I updated it myself.

Sorry for my ignorance but wheres the root of my storage card what file name exactly should i seek i already rename the file to TOPAIMG.NBH and place it in different folders of the storage card via file explorer and its seems where i have place it doesn't work, i go to the bootloader in the tricolour screen it doesn't appear any instructions after i waited like almost a minute each time i've try, it says loading pretty fast like almost in a second and the info appears and that's all , I touch the screen and press all the buttons and nothing happens... thx again

The root is the "base directory", where all the folder names are listed. Just copy it to there below the folders, not in one. That should resolve it. A lot of folks have issues figuring out where/what the root is so don't feel bad, you have lots of company. No reason to feel ignorant for not knowing something, NO human knows everything, even though there are a bunch running around who think they do.