XP Hangs before login screen

I installed all of the critical updates on my hp ZE4145 laptop and now when I turn it on it comes up to the Windows XP Home logon screen and just stays there. It does this for every type of boot I have tried. Safe Mode; Safe Mode Command Prompt; Safe Networking; last know good etc. I tried to boot off a win 98 CD and it said the c drive was invalid

Any help would be great