Trouble installing Win 7 x64 on Aspire 4750G - No Device Drivers Found

I recently bought an Acer Aspire 4750G with no Windows pre-installed (i.e DOS).

I downloaded Windows 7 x64 Professional Edition .iso from the official MSDNAA website. I used Windows 7 USB/DVD Download Tool (run on Windows XP SP3) to create a bootable USB flashdisk (Sandisk Cruzer Blade 8.0GB). Note that the file format of the flashdisk is turned to NTFS.

Next, i inserted the flashdisk into the USB3.0 port of my 4750G, when into BIOS and changed the boot priority to USB HDD - Sandisk Cruzer Blade.
As usual, I saved the changes, exited the BIOS and reboot. Also note that the initial mode is AHCI.

Booting from flashdisk is successful. I was able to enter the setup. The first screen prompts to select country and keyboard. The next screen shows the button "Install Now".


When I clicked this button, the setup does not lead me to the License Agreement screen. Instead, it displays the following message:

A required CD/DVD drive device driver is missing. If you have a driver floppy disk, CD, DVD or USB flash drive, please insert it now


There is a Browse and Rescan button at the bottom.

I had previously downloaded every driver for my Acer Aspire 4750G, hence i extracted those in .zip and copied them into the same flashdisk and restarted the setup again.
When the No Device Driver screen appeared, I clicked on the "Browse" button and tried to navigate to the driver folders inside the flashdisk. But I cannot find them, because the directory of the bootable USB flashdisk is completely different.


Not running out of idea, I copied the driver folders into my external harddrive (I don't have another flashdisk), connected it to the USB2.0 port and restarted the setup. Now I can navigate through the external harddrive to search for the driver folders.


The setup recognizes the .inf files (The screenshot below shows the chipset drivers)


But when I press Next, it loads for a while but then displays:

No new devices could be found.
Make sure the driver files are correct and located on the driver installation media


I tried several other drivers such as the AHCI, LAN and WLAN but to no avail.

So now I'm confused. I tried plugging the bootable flashdisk into the USB2.0 port. Although the BIOS detected it and I was able to change the boot priority, I cannot boot from it.

I also tried to switch the AHCI to IDE, but the same error occurred.

Additionally, to verify the integrity of the bootable flashdisk, I tried running the setup on my computer (Windows 7 x64 already installed). I did not encounter the above messages and was able to get into the Custom Install screen and beyond (I did not try to install as it would wipe out all my data, obviously)

I also tried to use another .iso (Windows x64 non-SP1 which I installed in my computer successfully), but the same thing happened.

Update
My friend had the exact same laptop (in fact we bought them together from the same shop) but she did not upgrade her RAM (unlike mine). Using Universal USB Installer, she did not see the error messages and moved on directly to Custom or Typical Installation screen. When I tried the same program, it still showed similar messages.
The only difference between hers and mine is the RAM.

I tried to elaborate as much as I could. I am very sorry if the pictures are not clear enough. Please help me to solve this issue. I would also like to offer my gratitude beforehand

Solution

caveman7 said:

The fault appears to be the flashdisk. I used my friend's flashdisk (Kingston 4.0GB) to create a bootable flashdisk, and it works!!
When I tried to use my flashdisk to boot up in her 4750G, the same error occurred. So that means the error lies in the flashdisk.
Thanks guys for assisting me!! especially gregrocker
I hope my thread will help somebody else with the same issue.

How about burning a DVD of the download iso and try the install from there?