Windows NT employs about 150 Stop Codes. However, you encounter the following Stop Codes most frequently. For a complete list of NT's Stop Codes, see the bugcodes.h file in the Windows NT Device Driver Kit.
IRQL_NOT_LESS_OR_EQUAL 0x0A
This code is probably the most frequently appearing code, and it usually
results from a buggy driver. The most common source of the problem is that
the Virtual Memory Manager has detected a kernel-mode component's attempt
to access pageable memory when the IRQL is Dispatch Level or higher and the
memory is in the paging file. The IRQL must be below Dispatch Level for this
operation to be legal. Look at the modules listed in the Stop Code and stack
trace areas of the screen for a possible candidate. This code can also be
a side effect resulting from a driver not shown in either area that scribbled
on memory it shouldn't have.
UNEXPECTED_KERNEL_MODE_TRAP 0x7F and KMODE_EXCEPTION_NOT_HANDLED
0x1E
These two codes also show up frequently. In this case, the Microkernel's
processor exception handler has detected that a driver or subsystem has tried
to execute an illegal processor instruction, or a software instruction that
NT cannot interpret. The cause can be a faulty memory module or a driver
that has corrupted memory. The module information on the blue screen is usually
misleading in this case, making it difficult to identify the source of the
problem.
NO_MORE_IRP_STACK_LOCATIONS 0x35
With this code, if you've added a new virus scanner or someone has accessed
a shared volume over the network for the first time on the machine, the Server
device driver can be at fault. The Server device driver constructs I/O request
packets with a slot for every device driver on the path to the disk. Sometimes
the number of I/O request packets the Server device driver allocates is
insufficient, resulting in this Stop Code. Try increasing the
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ LanmanServer\IrpStackSize
setting to a number higher than 4 (or whatever it's set to) and see whether
the problem goes away.
INACCESSIBLE_BOOT_DEVICE 0x7B
If you see this Stop Code, NT is very early in a boot and cannot access the
disk partition that boot.ini is pointing to for the location of the system
files (where your \winnt directory resides). The disk containing that partition
is faulty, or the data on the disk or partition has become corrupt. I encountered
this code when I left an NT 4.0 distribution CD-ROM in my CD-ROM drive and
rebooted. The computer tried to boot from the CD-ROM, and NT displayed this
message when it couldn't continue. An NT repair install is worth a try, but
you'll likely have to buy a new driver or reformat, reinstall, and restore
backed-up data.