Sony cybershot DSC T90 got wet in rucksack one day when we went out walking. Now it won't turn on. Is this fixable?

http://www.nodevice.com/user_manual/sony/camera/dsc-t90-b.html
this user manual may help you

They most likely mean serial number.
An IP address is issued by a router and can change from time to time when you connect to the router.

This camera is beyond repair. You need to buy a new one.

The date and time (and a lot more) are automatically stored with every photo in its EXIF metadata. To print this, consult the documentation for whatever program you're using to print your photos. Depending on the program and the printer, you may print this information on the image, in the margins, or on the back.

Copy the video first to the computer and play it using vlc player( it's a free software that supports most of the video and audio files that other players can't)

cheers!

The actual working part of the camera is not affected as the picture is taken properly. But the display part of the camera is only affected.The wetness might have penetrated across the sides of display screen to the inner parts.The display part needs replacement..

There may be still some moisture inside, remove the battery again, open any doors in the camera and put it in an airing cupboard or something similar and leave it for a couple of days.

Meanwhile, have a look at your user manual, check out what the red alarm light means, it may give a clue.

Then try again.....................Good luck.

Open the battery compartment and remove the batterys and the memory card. Completly dry the camera as best you can without further damaging it. Let it set open up like this for about 5 to 7 days. Recharge the battery and reinsert the battery and memory card. If you have to reinsert the battery to recharge the battery, do so. If it still doesn't work, contact the factory for a repair estimate.

contacted Sony directly. They walked me through many troubleshooting procedures, and it needs repair for 141.00.... Cheaper to buy a new one from Ebay for 50.00