Keyboard won't work as soon as windows loads

[caseywan]

Problem is the keyboard does not work as soon as Windows loads.  It works up until Windows begins to load and I can get into the bios with the keyboard and it works fine and get into the Windows load screen to select safe mode or normal mode, but not after Windows loads. 

I have a networking password on the computer and I can't get past that screen.  The mouse works perfectly in that screen though.  I have tried 3 different keyboards and have tried USB and PS2 and have verified that all the keyboards work on another computer.

I tried taking the HD out and putting it in another desktop and got the same problem.

I had this problem once before a few weeks ago, and I just messed with it for about 30 minutes and kept restarting and changing the keyboard from USB to PS2 and finally got the keyboard to work again.  Since then I tried not to shut the computer down in case this happened, but have successfully shut it down and restarted it a few times since without problems until today.

Any help would be awesome.

Thanks

[caseywan]

Also I suppose I should post my pc specs.

I built the computer - AMD 3400, MSI mb, 1gb ddr 400, 300gb western digital hd, running Windows XP Pro.

I have AVG but have had some viruses that it could't get rid of and was planning on backing up and formatting the day this happened.

[dahlarbear]

1.  Motherboard.  If known, what is the model number of the MSI motherboard?  (I'm basically wondering what options are in the CMOS setup for that BIOS).

2.  Windows XP Professional.  What is your current service pack level - Original, Service Pack 1 (SP1), SP2, or SP3?

3.   Mouse.  You've indicated the mouse works fine.  Is it a wired USB mouse, a wired PS/2 mouse, or something else?

4.  Keyboard(s).  Are these wired USB and PS/2 keyboards?  Which keyboard type, USB or PS/2, was used for the last successful "normal" login to this system ?

5.  Windows Advanced Options Menu.  If you can get to the Windows Advanced Options Menu (Tap the F8 key about once per second or faster as you power up the system), does the keyboard allow you to use the up, down, Enter keys to select an item from the menu?  If so:

    a.  Try starting using the Last Known Good Configuration item.  This will load the registry values for your last successful "normal" boot.

or
    b.  Try starting using Safe Mode item.  You'll need the Administrator password for this option, if one is set.

If the keyboard does not allow you to select item from menu, please let us know.  Also identify which keyboard type you're attempting to use.

[patio]

Have you tried a brand new PS2 keyboard ? ?
Is this one of those MSI MBoards that has only one PS2 connector ? ?
They have had issues...

[CBMatt]

To eliminate a lot of these, you should try booting up with a different hard drive and see if the problem still exists.  I am actually having this exact same problem with my computer right now.  I suspect AVG 8.0 of leading to the corruption of my boot files.  All I know is that when I boot with a different HDD, everything works normally.

Do you have a floppy drive by any chance?