Bootload problems following an experiment with iATKOS OSx86 install

I'm having boot problems that seem complicated - every help article I've found on the web seems to be missing something or is not working. Here are the details.

Lenovo ThinkPad T410 running Windows 7 professional 64 bit. The hard drive has 2 partitions, the C: OS partition where Windows 7 and all my files/apps/etc. live, and one called SYSTEM_DRV.

I had created a bootable USB with iATKOS OSx86 and tried to install it. The USB boot loader gives me a GUI menu that shows all my drives, and previously I had gone through the steps of creating an extra partition to play around with this, and I tried to install it on that partition, but the installation failed and so I decided to back out of the whole deal. But I guess it made some permanent changes to my system's default boot mechanism first.

So now, when I boot just off the hard drive, I am seeing "boot0:Error". From googling this I am finding this is related to the OSx86 stuff I was trying out, and so I believe it is saying "I'm trying to load this OSx86 you installed but can't find it." So, I think that OSx86 replacement bootloader still exists, and is failing to load any operating system. It is looking for one that doesn't exist, and won't load Windows either.

Fortunately, when I boot from that USB I still get the menu to choose which drive to boot from and if I choose SYSTEM_DRV, Windows 7 boots just fine. So I know not all is lost, it's just the default boot behavior is not correct. As a side note, I was surprised that I had to choose SYSTEM_DRV and not the drive Windows 7 is on, that's what I would expect and what I've experienced in the past. I don't know if this is a Lenovo thing, or Windows 7 thing, or what. Maybe this is significant, maybe not.

Some more information:

When I boot into a Windows 7 recovery disk and go to the command prompt and do "bootrec /fixmbr" it says it succeeded. But "bootrec /fixboot" gives an error "element not found". Same with "bootrec /rebuildbcd", it gets started, scans for operating systems and finds Windows 7, but eventually fails with "element not found".

When I go to System Configuration -> Boot tab, I see NO entries in the list of operating systems. And the buttons and checkboxes on that tab are active but non-functional.

So I am not dead in the water - I can still boot to Windows 7 using this bootable USB I made, but need to fix this.

Any ideas?

Since the OS you installed is Apple I suggest you confer with them in their own forums: Official iATKOS Website ? iATKOS and OSX86 Project

To recover Win7 boot confirm the 100mb System Reserved (preferred if you have it and it was previously booting Windows) or C is Partition Marked Active, then run Startup Repair - Run up to 3 Separate Times to test and repair all parameters which involves quite a bit more than merely running the dated XP-era bootrec commands.

Thank you Greg! Marking the partition as active was the key.

Glad it helped.

Make sure you have System Recovery Options on F8 Advanced Boot Options now or else run all three Startup Repairs to finish repairing all parameters.

What I would do going forward is try these test installs virtually or on another HD with WIn7 HD unplugged. If it's a keeper, then when you plug back in the Win7 drive set it first to boot in BIOS Setup, trigger the other HD using the BIOS Boot Menu key given on first screen.