Did you disable anything MS config ?
Its starting to get a little bit messy :/.
I'm sorry but I dont really have anymore ideas ans it's pretty hard to troubleshoot the problem if you never really seen it exactly

. Maybe you forgot something or did something else on the way ? There are really a lot of minor factors that could mess up this.
I would play around a bit ( you can enable some of the options that you have disabled earlier and check whats happening etc ) and let me know if u found out anything else.
If nothing works there is always /format c:/

.