Hi
I have a blackberry 8700
When I bought it, it worked fine until I synchronised it with my computer. Now when I turn it on the little red light comes on and then it goes off and the white loading screen comes up. But then it turns off and just keeps repeating this. What can I do?

Welcome to the forums.

You'll need to download the OS for your device from your carrier. A list can be found here:

BlackBerry Operating System Downloads - BlackBerryFAQ



Then follow the instructions here:

What to do next if Jl Cmder will not connect and wipe - BlackBerryFAQ

Thanks
But how do you change the command prompt so you can get in that way?

type in cd c:\

leave a space between cd and c:\

or you can just type:

cd C:\Program Files\Common Files\Research In Motion\AppLoader

and it should go straight to that directory

I have it all working

But how do I install the OS now?

When you say, "I have it all working" what do you mean? The above procedure should have installed the OS. Do you still have 507 on your device?

What I mean is that I have have everything set up to install it but when I connect it nothing happens.
It just says 'no operating system is detected please see administrator'

I have downloaded the right OS file and setup that but nothing happens on that either

Did you delete the vendor.xml file located in c:\program files\common files\research in motion\apploader?

While on the table the phone lit up as if a call was coming in and then white screen/hourglass came up. Then, phone went off. Red light then appeared. This cycle has been happening over the last hour. Called tech- removed battery- cant break the cycle. Help! Good news is i backed up about 3 weeks ago but still will miss the new numbers added so trying to avoid at all cost.

Follow this procedure:

What to do next if Jl Cmder will not connect and wipe - BlackBerryFAQ.com

You'll need to reload the OS to your phone.

excellent procedure, i just used the reload trick for an 8700v, that Voda said should be thrown away, as all i was getting was the red flashing light, after an unsuccessful firmware upgrade.

I wasn't paying £250 to replace it. many thanks, i now have a spare for our BES system.