Wow your realyl desperate to find out luckilly i got your solution right here, Go to start>Control Panel>Performance and Maintenance>System Restore, then chose a date before the problem happened, System Restore sets you back before the problem happened. After that, Lol, Before that it should be fine.
Wrong. System Restore fixes system files, not program files I believe.
Besides, even if it fixes program files, it's not the best way. Also, you DON'T have to buy another key if you reinstall. Once you buy one key, it's yours forever and you can use it as much as you want until the end of time or you.
Here's what you REALLY do:
1. Delete all of your Blockland files via Add/Remove Programs in the Control Panel.
2. Reinstall Blockland.
3. Re-enter key.
4. Download and extract GTA map, and DON'T delete your default maps.
5. Play.