Default [Q] Help after failed flash and reboot cycle

Hello. I have been waiting a while for a CynogenMod for the i5800 and yesturday I attempted to use it on my phone.

After rooting via z4root apk, I downloaded the free version of ROM Manager and when it asked select your model of phone the i5800 isn't on there so I picked the ZTE Blade as it is another low end phone. ROM Manager then proceeded to make a 'backup'.

Then went onto trying to install from .zip using the current build for the i5800 from here and selected it from the recovery menu only to see after a long boot up that it had booted into the stock ROM albeit still rooted. Now everytime I turn my phone off it acts like its been wiped and has 0mb of memory (should have about 150 or similar) so I can't get a root explorer.

Hopefully this is a simple solution as its still on android2.1-update1 aka what the phone shipped with and I believe Samsung is in the process of sending out a 2.2 update so could someone please say how I can make sure the phone has no evidence of flashing and how to stop the constant wiping of the phones memory so that I can sell the phone without any risks.

Many thanks, JTS.