rkwan should be better person to answer

I am a beginner nia, can't answer you.
is ok.. let the PRO do the job
haiyo.. follow us on this thread quite some time dy leh.. haha, u must be lazy to read previous post huh.. rite? haha
anyway, here is my brief explaination..:
ROM (read-only-memory) is actually a hardware that act as a Harddisk in a pc.. it stores all the windows files, OEM software like HTC camera, TF3D, Xperia Panel and all those needed stuff to run our device...
but, most of the time, ROM is refer as other thing as we all are talking about. ROM here we refer as a file downloaded from internet that contain all the windows system core file, each rom is differentiate by Windows Mobile Build No.. latest official wm6.1 is build 21043, while wm6.5 is 21222. then rom can be cook by ROM COOKER. they can implement 3rd party software inside the rom and even throw away so called "useless stuff" inside the ROM. so, in anyway, 3rd party rom is always have better stability (it depend too sometimes), and make ur device more Usability (like implement TF3D 2), and make ur device faster or bigger space (by throwing away stupid stuff and tweaking of registry in a ROM).
since rom is read-only-memory and not writable like pendrive do. so, i nid to flash it. yes, flash.. by mean of flash or write the ROM block by block.
so FLASH ROM mean format n install a new faster windows mobile into our PDA.
hope u get it in anyway.. a bit too long this time..
hey hey bro.. dont say like tat.. juz try your best n see what urself understand also mar.. remember we are all beginner actually.. unless there is rom cooker here that can cook rom for us..haha..
i also try my best to explain too.. hope everyone understand wat am i talking about..
share share our experience and knowledge..
oh ok.. thx for the explanation