I went to put another SIM card in my Curve 3G 9300 and ever since then it wont get past the Blackberry logo (white screen)!

I've taken out the SIM and memory card and still the same thing...

Is there anything I can do other then taking it back to the shop to be fixed?

It's not a solid white screen with no text or images or anything? If not, then good.

With the power on, remove the battery, and wait a good minute. Put the battery back in and give it 20 or 30 minutes to find out for certain whether it is going to finish booting. Watch it to make sure it isn't in a re-booting loop.
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I've done that, but still nothing :( It's and got the Blue blackberry logo and the blackberry name on the screen.

I can't tell if it's a re-booting loop :/

I've managed to sort it out, I used Jl_Cmder to do a factory restore... I'd like to know what went wrong in the first place!

JL_CMDER was going to be my next suggestion,

As far as what went wrong...What did you do prior to the problem? Third-party apps? Third-party themes?

The memory card would have been something to check, and you did, and turns out that wasn't it.

If you have not restored all your apps yet, I would only reinstall what you absolutely need right now. Wait 24 hours and test. Then add the others one by one, and test 24-48hours in between.

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Nothing tbh, all I did was put another SIM in it like I have done a few times before...

Beats the heck out of me. Is it repeatable?...If you do it again with the other SIM, does it happen again? If not, I'd chock it up to one of those freaky things that happens and you hope never to see again.
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Well, I've put the other SIM I used when it messed up and it was fine this time round!!

Good. Hopefully that was the last time you'll ever see that happen.
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Well, it happened again after a battery pull :(

I did a full wipe and a clean install... Lets see how this goes.

Strange.

But with that one SIM and not the other? In other words, the question will be if it happens only with the one SIM, or if that was just coicidence. My bet is on coincidence.

Post an update when you get the chance. If it keeps happening, start looking at third-party apps and themes installed on the handset.

Are the SIMS from the same carrier?

Try formatting and reinstalling the OS....other than that...umm...Bueler?

blackberry generally requires a 64k SIM. I wonder if the second SIM is smaller. either way it should not cause the issue. real wierd.

Well, after I did a full wipe on Sunday just gone and a clean install, it now seems ok! The SIM im using is my 3 (UK).