I shot alot of pictures on my sony cyber-shot W55 and when i wanted to view them it says file error

It may be a problem with the memory card. Try the card in a card reader or another sony camera. If it works ok then, you've a camera problem.

If it fails also, it's a card problem, the files are corrupted somehow, the only thing in this case is to re-format the card in you camera, it will be one on the menu options.

The trouble is, when you format, it clears every thing off the card.

Another way is to buy a spare memory card, always handy, if that work ok straight away, again your first card has a problem and probably needs formatting.