The most helpful piece of information would be the error code that the blue screen gave you. It is always a hexadecimal number, 0x000000##, where ## is dependent on the error.
If you don't have that info, then be sure to write it down if it happens again. I recommend that you make sure you have your data backed up.
I'll layout a few things you can do. Keep in mind I'm waiving my consulting fee
If you suspect that something is wrong with a system file, perform the following steps. These steps should not harm your computer, but complications can arise so it is highly recommended that all important data is backed up to an external drive, USB flash drive, DVD collection, etc.
In XP, make sure you are logged into an administrative account
1. Click Start.
2. Click Run.
3. Type
cmd. Then hit the enter key.
4. In the command prompt, type
chkdsk /f C:.(<-- Don't type this period) When you restart your computer, Windows will check its system files to make sure they are not corrupted, and will make any corrections that it can.
In Vista.
1. Click the "Orb" with the Windows logo on it on the taskbar.
2. In the box that says
Start Search, type
cmd.
3. Right-click on the
cmd.exe that shows up under the
Programs heading.
4. From this context menu, select
Run as administrator. Type in your password if prompted.
5. In the command prompt, type
chkdsk /f C:.(<-- Don't type this period) When you restart your computer, Windows will check its system files to make sure they are not corrupted, and will make any corrections that it can.
If you suspect it is an issue with drivers you have installed, you can go to your manufacturer's website(s) in order to upgrade drivers and firmware. For example, for Dell machines you can go to support.dell.com and type in your service tag.
To see if you have any critically missing drivers, perform the following steps.
In XP, make sure you are logged in as an administrator. In Vista, you just need a password for an administrative account.
1. Right-click
Computer (
My Computer in XP) on either the Start Menu (XP) or the orb (Vista).
2. Type in any passwords/click continue in Vista.
3. On the menu on the left, click on the
Device Manager.
4. See if any of the devices are labeled
Unknown or have a question mark/exclamation point icon next to them. If that is the case, you are missing a driver. To install it, you will have to go to the manufacturer's website or find the media that came with the hardware.
If you need any help with any of this, feel free to ask.
P.S. The blue screen stayed up on the screen because there is an option in the control panel that you can set to prevent it from immediately rebooting. The first thing I do whenever I install a Windows system is turn off this "feature" so that I know what's wrong with my machine if it fails. Unfortunately, I can't remember where it is, but if anyone wants the info just send me a PM or post and I'll find it.