Hi all!

I got my N900 around June last year, has been working perfectly after I updated the OS shortly after (had some random shutdowns before I did).
Recently though I got a memory error (think it said low memory or inaccesible). Since then the phone couldn't even start, so I sent it in for repairs after attempting reinstalling the OS. I tried on my Windows 7 64b but discovered the flasher program doesn't work well on this, tried it on a windows XP 32b system, worked better but didn't fix the phone.
When I got the phone back from repair everything seemed to work again. Unfortunatly I discovered that there were still memory issues.
THIS is what I need help with.
The primary issue is I can't delete anything on the memory, pictures and music etc. If I manage to delete them they reappear after a restart. Tried deleting via the phone and managed to connect to it via computer and tried to cut and paste [elsewhere].
The most common fixes I've found have been to connect the phone and then eject from windows to force the memory from read only mode caused by improper disconnection of device. This didn't work.
Also tried the rootsh fix with umount, fsck and mount through x-terminal. This first seemed to work but the pictures eventually reappeared.
Tried using the chk dsk in windows xp and the autofix in windows 7, the latter took ages but didn't report any issues at all.
So, should I send the phone in for fixing or is this where I do the flasher emmc? Does this completely wipe the user memory so I'm back at square one with a, hopefully, functional phone? If so, is there anything specifically I need to think about when doing this so I don't cause any more harm to it?