Win7 Home Premium 64-bit won't boot: iusb3hcs.sys is corrupt  

Hello everyone,

I bought a Toshiba laptop from a friend. Toshiba Satellite® C855-S5206 15.6" widescreen Laptop (Black) | Laptops | Computers | us.toshiba.com

It came pre-installed with Win7 Home Premium 64-bit

My problem started when I tried to make a hard disk partition using Mini Tool Partition Wizard/MTPW. I have used this tool before and it was pretty easy to use. My big mistake was forgetting to create a backup or system restore point.

In this laptop, I have gone through the MTPW partition process. Afterwards, it requested a computer restart which I did. Then the partition process failed or stopped halfway through. My thinking is that I either made a bad partitioning instruction (which the application failed to implement)...or the partition process just didn't work.

The Toshiba laptop or Windows itself offered a startup repair process but it failed to repair the problem. The startup repair returned a report saying:
Root cause found:
Boot critical file c:\windows\system32\drivers\iusb3hcs.sys is corrupt
Repair action: File Repair Result: Failed.
Error Code = 0xc1
Time taken = 1185ms

Repair action: system file integrity check and repair
Result: Failed.
Error code = 0xc1
Time taken = 343 ms
------------------------

I was unable to run SFC or system file checker from the command prompt (as Admin). I tried to force it to run by using this command (this was used successfully by others online)

sfc /scannow /offbootdir=[specify CORRECT drive here]:\ /offwindir=[specify CORRECT drive here]:\windows

it still won't run. The reply was "Windows Recovery cannot run this operation" or something to that effect.

I cannot run chkdsk too. The laptop won't boot. Before the boot reaches the Windows GUI, the Error/Startup Repair process would start. This is a never ending loop.

I think if I can make the laptop boot up, I would be able to run chkdsk and/or sfc.

Now, I would like to get ideas from you on how to make this boot up.

Questions:
iusb3hcs.sys is corrupt. is this driver really a boot critical file? Since my laptop won't boot, does this mean it concerns the MBR? any other possible cause of iusb3hcs.sys becoming corrupted?

Would simply replacing the corrupt file (iusb3hcs.sys) with a working/clean one, doing copy and pasting, work? (I have read about this online)...How should I go about this in the command prompt?
copy iusb3hcs.sys [source: USB] target: C drive] ...like so?

Assuming I get my laptop to boot up, can I simply erase the corrupt file, and copy and paste a clean iusb3hcs.sys to my Windows\system32\drivers folder?

I do not have a Win7 Home Premium CD, but I do have a Win XP CD.
Does Win XP have the iusb3hcs.sys file/driver?

My ideas are
1. to boot the laptop using the Win XP CD... or install Win XP, then
a. try to run chkdsk or sfc.
b. repair the corrupted file with Win XP CD's contents (if it has its own iusb3hcs.sys file)
c. would FIXMBR at the command prompt help in this case?

2. I learned I can make a bootable USB drive using Mini Tool Partition Wizard. perhaps, I'll repeat a., b., or c.

3. I am currently downloading a Windows 7 ISO file. I will create a bootable USB drive from this. Do i need the product key to make this work? Perhaps the repair install/built-in startup repair/recovery option from this might work. I might try a., b., c. here too.

Would any of these work? Any other ideas?

This laptop has very few files in it, but I do not want to do a clean install. I simply want to remove and fix the corrupted file.

I will continue to find the solution online.

Thank you very much!