Microsoft has confirmed that KB 977165 (Security Bulletin MS10-015 released on February 9th, 2010) can cause blue screens (STOP: 0x00000050) on mostly XP systems (but some Vista and Win7 too) that have been previously compromised by the Tdss rootkit that started spreading last November. What makes this particularly painful is the computer is incapable of booting, not even in Safe Mode.
Microsoft pulled this update from Windows Update circulation to reduce the impact until an update patch can be released. Companies that use SMS/Configuration Mgr/WSUS to distribute updates need to manually decline the update.
A Microsoft Support Engineer provided the following manual workaround (try this at your own risk / I am not responsible if you actually follow this advice)
1. Obtain a bootable disk or USB stick with Windows.
2. boot from the Windows CD/DVD/USB and start the recovery console.
3. Once the recovery console is launched, type: CHDIR $NtUninstallKB977165 $\spuninst and hit Enter.
4. Then use the following command: BATCH spuninst.txt, hit Enter again, and type: systemroot, and again Enter.
5. At the end customers will need to type: exit. Simply trying to startup Windows without the recovery console will not work, no matter the boot options selected, as the computer will not reboot and Windows will always end up displaying the BSOD.