Problem with K800i

Don't think I have this in the right forum, not even sure if it should be here at all but I'd be very greatful if someone could help me with this. If its in the wrong place, feel free to move it please.

I got a k800i which was originally with O2 Ireland, but I got it unlocked (just by some guy in back streets) and I now use it with Meteor. A while ago I was trying to get an MMS through, and it wasn't showing correctly, so I turned my phone off then back on again. Pretty sure there was nothing suspicious with the MMS, it was from someone who wouldnt have a clue when it comes to that. When I turned it back one, it done its little vibrate thing like normal, but the screen stayed black and it let out a beep, but one I'd never heard before, very low sound and just sounded broke. this is what happens every time I switch on the phone now, and the screen remains illuminated, but just black.

Does anyone have any suggestions on how to solve this please? Any help would be fantastic, cheers.

Did u try removing the battery and sim?

You should make a full reflash with XS++

use master reset first, if it won´t help, so remove battery for 2 minutes, and if this won´t help, so make fullflash

I've taken battery and sim out, yes.

How do I do a master reset or full reflash?

make a full reflash with XS++

search for .bin and .fbn according to ur phone model and cid no... and flash it

yes full reflash
main is .mbn not .bin
FS is .fbn
make sure you get firmware that matches your phone same cid: as the erom cid

Ok, I got XS++ and tried putting on some custom firmware? it got to 160000 and stopped and didnt change from saying that so I just stopped it.

So I then used the Sony Ericsson update program, and now there's slight functionality, well, more than before, like whenever I switch the phone on a purple box (like when a message would appear normally e.g. your balance) appears and it has a tiny font with random spaced out letters. whenever you press the power button, it brings up the normal menu showing the profile options, but it just has the pictures at the side for each profile, it doesnt have any text beside them.

any ideas?

use master reset first and use XS++ 1.6.8

how do I do a master reset? if it's something to do with using the phone's menu, then that will be tricky cause i can't access anything on the phone itself.