Alright, this one got me stumped...
Bear with me. This is a long story:
I'm trying to help out a family member with a clean install of Windows 7 (Ultimate, 32 bit) on his ASUS A7Sv laptop.
Laptop came originally with Vista, which got hosed by a virus, including the restore partition.
ASUS doesn't support Win7 on this laptop, but it should work.
Hardware is quite common: Core2Duo on an Intel ICH8M chipset.
Win7 should find all hardware out of the box. (Except for the special Hotkeys, but I can always install the Vista Hotkey utility, which is known to work on Win7.)
Have to install from USB as the buildin DVD player is broken. (I removed the DVD-drive from the machine so it can't interfere with the install.)
I've got an USB-key Win7 installer which I know is good. I have installed about 30 machines with it before this. (And even another system after this just to make sure the USB isn't damaged.)
The USB install has SP1, hotfixes upto December 2012 and all known SATA/SATA-raid & USB3 drivers slipstreamed into it.
I installed another laptop some months ago, (different brand with nearly identical hardware,) with this same USB-stick without any problems.
Setup proceeds as normal until the point where it need to load the mass-storage drivers.
Then it asks for a CD/DVD driver.
I know this is not really the CD/DVD driver: Win7 wants a mass-storage driver.
I have tried every mass-storage driver I can get my hands on: ICH8M, ICH8, ICH8R, old versions, new versions, the Vista version supplied by ASUS. Even the JMicron drivers for the eSATA (which I'm not using). Just to make sure I also tried the Intel Turbo Memory drivers, even though I don't intend to use these.
Nothing convinces Win7 to continue with the install. (Although it accepts these drivers, they are compatible with the hardware.)
Stupid thing is: If I run Shift-F10 and launch DISKPART I can see the HD fine. I can partition and format it without any problems.
Any ideas which driver Win7 is looking for ? Any other suggestions ?
(Don't bother suggesting re-plugging the USB-stick in another port. That only works if you booted from an USB port on Bios emulation so Win7 needs to rediscover the USB with it's own drivers. That is NOT the case here.)
Update: Tried it with the mSata cache flash module removed too. (Thought that might interfere somehow). No joy either.