I'm not sure how to boot to windows disk, but I wouldn't bother. In the past I've used Windows Repair AND CHKDSK and they simply do not satisfy. They take a LOT of patience / time / heat to your hardware, too.
I myself have just had an issue with chkdsk. I cloned my Vista install using Winclone, and restored it after resizing my partition using BootCamp Assistant. Everything goes great until chkdsk decides it doesn't like the feel of my cloned data. Chkdsk is stubborn, takes hours of time, and then half the time it is still not satisfied with it's own fix. (Same goes for Windows System Repair, I find).
Rule Of Thumb - When ANYthing smells bad in your Microsoft set-up: gather your files to external storage and do a Clean Install of Windows.
In the case of chkdsk, just click a key to go around it, and then start saving your valuables to external storage (USB stick, burn some disks, whatever is easiest). My opinion is that as wonderful as Winclone has been in the past, you can only count on it as an emergency device. I tried to use it to "save time and effort" by cloning a fresh install of M$ (by-passing all the laborious effort of updates, AV, aftermarket software, etc) but the clone is never perfect enough to pass the chkdsk test, so it is best to Clean Install. Or better - make a SlipStream disk.
For the adventurous (or those frustrated or short on time) here is an experimental CHKDSK workaround: disable CHKDSK from starting up by using the /x switch on chkntfs command in command prompt. The /x switch will exclude a drive from the default boot-time check. If you need to disable chkdsk on drive C (for example):
chkntfs /x c:
If you have 2 drives, C and D, disable chkdsk with the command
chkntfs /x c: d:
I have NOT tried this yet - I intend to someday. Google it for further details. In the end though, no matter how you work-around chkdisk, a fresh install is always the Answer To Avoid Disaster in Windows.