Can't download from Marketplace anymore

[Guest KazDub]

So, I was bored last night and swopped out my Vodafone SIM for the Orange one that came with my phone. I just wanted to see if it could be used for anything since I unlocked the phone and de-branded it. Anyway, it seems pretty useless. I put my own SIM back in and went on to Marketplace to try and download a FM Radio app. I can get on to MarketPlace but anything I try to install results in a message saying that the download was unsuccessful. Has this anything to do with me putting the Orange SIM back in for a while? I have been installing apps without any probs recently and this is the only thing yesterday that I did that could have had any impact.

Any ideas of what I've done and how I can fix it?

Also, just to confirm, the Orange SIM can pretty much be binned at this stage, right?