I am using Multibit. How to overcome if my computer burns off?
First store your wallet on a disk with a key. Second copy your wallet.dat file. All the information necessary to recover access to your bitcoins is stored in the wallet.dat file. Or if you prefer you can use an online wallet to save your bitcoins. That is independent from you computer
There is a lot of info about securing your wallet on bitcoin.org
I do the following:
- Encrypt my wallet with "Password1" and backup to a file
- Zip the file with "Password2"
- Store the wallet in all dropbox/skydrive/googledrive/amazondrive
So, even if your computer burns off, you still have your wallet in cloud drives, and even if one or two of those cloud drive providers go out of business or loose your wallet because of bugs in their software, you can still restore it from other cloud drives.