Serious 6600 Problem

hey ppl,

Thought i'd post on here to see if someone would be able to help me with my 6600. Ive just changed from my 3650 to a 6600. Had my 6600 about 4 days now, and have had my 64MB card from my 3650 put in my 6600.
Everything was working fine, until today...

THe phone has majorly slowed down in opening up the menu, and other parts, in general everything has slowed down in doing proccesses on the phone.
But also when i started to receive texts the bar at the bottom with "1 Message Recieved" now doesnt appear, along with no sound, or the phone lighting up when i get a message. Theres now just the small envelope icon in the top right of the screen.
Does anyone know why this is happening?

I did change the message memory from the card to the Phone memory, to see if that would help, and that seems to have sorted the speed of the phone, but still the problem of receiving messages is still there.

So im wondering....is this the memory card causing this problem, as its not an official nokia card and i had it previously in my 3650?

Ive only got 2 appllications on my phone now, Torch and FExplorer.

I was thinking would a hard reset solve this problem? or is it a case of taking it back to the carphone warehouse for a replacement??

any help would be greatly appreciated