well I am at work so I cant really do it over the phone, but if you post your questions here, i will get back as soon as I can. but sprints latest stock rom just came out yesterday. if you go to htc's website you can download that rom which has windows 6.1 and the latest radio, from there its just loading nuespl and flashing your rom. I am assuming you are on sprint since you said you have the mogul.
I just realised part of what I said might gget your confused, the latest official rom shoudl have windows 6.1 stock now, but if you flash a custom rom, you have to make sure it is 6.1 although 99.999999999% of the roms out there are windows 6.1 nowadays