user1220: I have downloaded it onto my windows pc 3 separate times and each time it goes to start the program it shows the bitcoin wallet "loading addresses", then it's "loading block index" then my computer makes a noise and I receive this: error loading blkindex.dat. I click OK and it disappears with no options on how to fix. 
I'm not very computer savvy. Please help. 

user1171: Close the client, go to C:\Users\(Your Username)\AppData\Roaming\Bitcoin and delete everything in the folder except for wallet.dat - do not delete wallet.dat under any circumstances (and empty your Recycle Bin), then restart the client. Somehow your block index file became corrupted.

1220: <p>I have downloaded it onto my windows pc 3 separate times and each time it goes to start the program it shows the bitcoin wallet "loading addresses", then it's "loading block index" then my computer makes a noise and I receive this: <strong>error loading blkindex.dat</strong>. I click OK and it disappears with no options on how to fix. </p>

<p>I'm not very computer savvy. Please help. </p>
 1171: <p>Close the client, go to C:\Users\(Your Username)\AppData\Roaming\Bitcoin and delete everything in the folder <strong>except for wallet.dat - do not delete wallet.dat under any circumstances</strong> (and empty your Recycle Bin), then restart the client. Somehow your block index file became corrupted.</p>
