Bitcoins are only generated every 10 minutes (on average), so it would probably not be worth it for a company to dedicate a huge cluster of computers to it. At most they could earn 50 BTC/10 minutes, no matter how much computing power they'd throw at it.
It get's more interesting if a company could calculate blocks faster than all the other nodes combined. Then that company could forge the complete chain of transactions.
I think there are even numbers floating around in the BitCoin forums as to how much it would cost to build such a server farm atm. So yeah - with enough money you could ruin BitCoin, but why would you be motivated to do so? Also, it gets harder every day, as the network of nodes grows.
Yes. Though it would be hard to just out-compute the hashes without the community noticing. Just to put it into perspective: currently the network is crunching away at 16344 TeraFLOP/s ( http://bitcoinwatch.com/ ).
It get's more interesting if a company could calculate blocks faster than all the other nodes combined. Then that company could forge the complete chain of transactions.
I think there are even numbers floating around in the BitCoin forums as to how much it would cost to build such a server farm atm. So yeah - with enough money you could ruin BitCoin, but why would you be motivated to do so? Also, it gets harder every day, as the network of nodes grows.