TDSS
Maybe someone met? Creates malicious files C:WINDOWSsystem32[RANDOM].dll and C:WINDOWSSYSTEM32DRIVERS[RANDOM].sys, infects the MBR. There are several modifications, most are removed only by about three of the best antiviruses.NorthSouth
This is exactly its feature. Not all antiviruses do a good job of infecting the MBR. At one time, AVG could catch 1 modification (only under WinXP 32, but not Win7 64), BitDefender - all versions for both axes, Avast! could catch another version, Dr.Web could not catch another version for both axes, and Kaspersky caught everything (not for nothing they have a separate utility).
Virus.Win32.Sality.aa, for example, also uses a driver, also uses autorun and disable safe mode, interferes with AVZ and CureIt! (sometimes it definitely interfered).
As for Conficker (Downup, Downadup, Kido), the following is known:
According to McAfee, the damage caused by the virus to the online community is estimated at $9.1 billion, second only to the damage caused by email worms like MyDoom ($38 billion). ) and I LOVE YOU ($15 billion).
By the way, the garbage came out on Win7 x64. I infected it for the test, then Windows did not start normally. I had to treat through LiveCD.