As a test and a possible assist, try...
http://www.terabyteunlimited.com/bootit-bare-metal.htmTry run this from the DVD and select "maintenance". You can also install it as well for a trial, it is worth getting though.
First things first though, select "maintenance" and delete all the partitions. Then install it and create a second partition or use maintenance to create a partition.
The bonus is if you pre-partition the drive you won't have windows 7 then create multiple partitions.
support is here
http://www.terabyteunlimited.com/support-bootit-bare-metal.htmp.s. if you want a good drive setup, get a small cheap SSD that supports trim + native command queuing for windows and Momentus XT for storage. Backup the Momentus XT as lots of complaints about stability, but I have two from the last few months and they seem rock solid to me. (One in PS3, one in PC). If you only want one drive I would get the Momentus XT, as it could be reused well in other devices later.
and maybe only connect one drive when installing windows 7... although I think I had both connected and it was OK.
oh and if you find the problem is in the optical drive, a good brand for Blu-Ray I find is Pioneer, personal preference I suppose. I think Pioneer 206 is latest. For optical drives ASUS re-brand whatever is best, sometimes (often?) that is Pioneer, so a new ASUS is also a safe choice.