Computer Hangup

[TitanMn]

Still trying to figure out what exactly happened, hope someone here will have the answer. I was playing a few games on my laptop, I shut it down, started it back up 5 minutes later and it starts hanging itself up on the login screen with this message that says Windows has detected an unauthorized change to the system. It gave me two options, to go to the Windows website or close the dialog. I clicked the button that said to go to the website to learn more, after about a minute or so it says it can't find the page, so I shut it down again, went on my friends computer and burned myself a boot disk, thinking that something got on my computer.

Well, after I ran a complete scan with Avira's boot disk, it didn't find anything malicious on my system. I had it scan the boot sectors only and it gave me an alert that said this.

WARNING:[iO error on file] Master boot sector {disk /dev/hda}

So, the question is this, how can this be fixed? And if it can't, how can I save important docs?

[rgabbard]

Sounds like your MBR is corrupted. What version of Windows are you running?

[TitanMn]

I'm using Windows Vista Home Premium 32-bit.

[rgabbard]

This should help you out. You'll need to have a Vista disk to do it though.

http://support.microsoft.com/kb/927392

[TitanMn]

It worked. I'm grateful for your help.

Out of curiosity, how does something like this even occur? A sudden jar to the HDD?

[rgabbard]

Honestly, I have no idea what could cause it. I've had it happen a couple of times, once it was fixable, the other time I had to reformat.