Are you sure your OS hasn't attempted auto-updating which failed?
Is it continuously occuring?
So far from what your've told me I assumed you couldn't get place boot,
however if you can I recommend first checking your virus scanner is compatible with Windows 7.
Some possible causes / solutions:If it's continuously or regularly doing on boot and you can't get past that point, the best option would be to restore your original stable system state and re-update it. When your computer is starting to boot, tapping F8 should display a boot option menu and select 'Last Known Good Configuration'. This should help resolve bad driver issues by rolling them back to when it was working fine.
orIf you have a huge amount of memory installed the OS might not be able to handle this, we're talking about hundreds of GBs! I believe there was a hotfix released for this, but surely not an issue unless your doing something extreme.
http://support.microsoft.com/kb/979903orIf the crash occurs randomly - your computers memory might be damaged / corrupted. When it's reaching and reading the damaged memory it would crash. In which case you should check your memory instead on boot. Find and remove/replace any damaged memory. To do this you can use a memory stress test tool like...
Windows Memory DiagnosticThis application from Microsoft you can download and install onto a disc, then boot the computer using it.
It will take a while but scan your computers memory to check for errors/corruption when accessed.
http://oca.microsoft.com/en/windiag.asporThis crash can also be brought on by spyware and adware or virus infections trying to access a memory address they don't have permission to. Ensure your system is clean of malious software, if your still having the issue.
orThe crash occurred by an incompatible Virus Scanner attempting to scan the memory causing the crash. Ensure your virus scanner is supported and get an update for it or replace it if not. I'm betting this is a good chance due to the behavour you just described, it's not working with Win7 - right after the win7 animation it will be loaded and start scanning, randomly crashing. Older virus scanners never supported this OS, until it came out and they made newer Windows 7 versions.
'ntoskrnl.exe' - is the kernel image, a major core component of the operating system.
Parameter 1: memory address that was referenced improperly
Parameter 2: IRQL required to access the memory
Parameter 3: value 0 = read operation / value 1 = write operation
Parameter 4: address which referenced memory (attempting the access)