In the good old days of Windows up to XP, you could delete the windows partition and reformat and be back in business with no adverse affect on your hard drive or the performance of your OS. But I've gone through more than a half dozen partition programs and disk wiping programs in an effort to cleanly upgrade from the evaluation version of Windows 7 to an OEM version, and each time, Windows 7 resists being fully erased from the drive. Microsoft seems to be implementing some boot encryption or or hardware bios routine that leaves traces of the OS even after Windows 7 files and partition are gone. Since I can't find much about this issue on the Net it may be that my particular software configuration, particularly the firewall that I use, Agnitum Outpost. But I had this issue with a variety of hard drive and motherboards. The only common factor I see is Windows 7 and the firewall, Outpost professional and/or Comodo and that the Win7 is installed in a dual boot config with WinXP in a separate partition. I've tried wiping both the partitions and the entire hard drive and get the results described above. I noticed the effects when I install Windows 7 on a clean hard drive compared to one one that had Windows 7 previously installed but erased. In the latter case, I'll sometimes see a message "checking registry" during the initial re-install of Windows 7 after the previous version was erased and/or get error messages after the OS has supposedly been cleanly install. This is not a boot virus issue. My PCs are clean. This problem is cropping up on at least a dozen computers I manage at home and at work. Like I said, with Windows 7, you seem to get one opportunity to get an install right on a virgin hard drive, and then the OS seems to try to preserve some remnants of itself no matter what you do to reformat or wipe the disk. The only tool I've found that actually gives me a clean hard drive for a re-install is the HDDerase.exe, driving wiping utility. But it doesn't work consistently. I was wondering if any other members had any ideas or recommendations or had experienced this problem at all.