help windows 7 wont boot ?

[wykd]

Hi guys

Just recently setup a computer for the GF, trying to install Windows 7 pro for her but it keeps going into bios now and I'm stuck not knowing how to continue.

Specs :
Main pc :
Z87 expert
128gb sandisk SSD windows 10
WD black for storage

Alt pc:
Gigabyte x88 up4
New SSD (windows 7)

Here's what I did :

All drives plugged into main pc

Downloaded ISO from Microsoft for x64 windows 7 pro and stored in my HDD

Ran install onto new SSD, plugged the product key ==> successful boot

Plugged new SSD into alt pc ===> no boot black screen

Plugged new SSD back into main pc , unplugged main SSD , ==> no boot but straight to bios

Plugged main ssd back in , ==> boot
Asks if I want to boot 7 or 10 , both work

Removed main SSD ===> no boot
Straight to bios

Set boot priority to new SSD, tried to boot new SSD ==> no boot straight back into bios

Firmware is installed for SSD
What can be the problem ?
Can someone please help me ?

 

[porterjw]

You need to do a clean install of Win7 while the SSD is installed in the 'Alt PC'.

Burn the iso to a DVD and install from there.

By installing Win7 on the SSD while it's hooked up to the 'Main PC', the boot files are being installed to the Win10 Drive. Hence, there is no MBR on the Win7 SSD so when you move it to the Alt PC, there's nothing to say "hi, Windows is right here, go and load it". And it also explains why you see both Win7 and 10 on the Main PC with both Drives installed, and nothing with the primary SSD removed.