Remove the CMOS battery for ~5 minutes, then try again.
You're likely going to need to do a windows repair, using your OS disc. However, you may need to change the boot order in the BIOS first. If you've got a PS2 keyboard laying around, or that you can borrow, try that.
i had this kinda problem with my new mobo installation on a hp desktop - it was getting going then stopped and asked-- " repair or run normally"?
it couldnt get past this loop start bios then run " repair or run normally"?
i had no recovery disc handy as the desktop shipped without one ------ so i stuck in my toshiba laptop recovery disc and this re installed the windows enough to get it up and running , i then installed the asus cd that came with the new mobo.even surfed the net after this for a while - great !
next i will access the original recovery section on the hp hard drive and ask it to take over as it is currently running the windows from my tosh.
any how i think if you are having probs stick in the recovery disc and if you dont have one , borrow one from a friend . worst case it will install a version of windows and get your computer running enough to ask for "authentication" in the meatime you can use this window of oppurtunity to reload yoru original windows