Shoutbox

I am running AVG anti-virus program running on my desktop, after switching on, AVG updates then said that there was a threat with some Trojan file and ask if it should be healed or remove to AVG vault, I selected heal and it says to restart and to my God! XP cannot be reloaded, as soon as it reaches the XP logo it keeps restarting over and over. Why did AVG allow this to happen and how can I rectify this problem? I backed up all my important files from my laptop through my router unto the desktop.  Cheers