Not booting up after screen replacement

Hi,

I've just replaced a screen on an iPhone 5s. When I was reconnecting the last ribbon cable wouldn't sit properly.

I tried powering it up and now all I get is the Apple logo, then a blue screen and the phone will restart and repeat the process.

I'm thinking I maybe shorted some pins together by mistake.

Any ideas on how to get around this?

I've reseated the battery and all over ribbon cables I can see but it's still the same.

Any help is massively appreciated.

Regards

Tom