You might see if you can install your Vista 64-bit driver for it using Compatibility Mode with Windows Vista selected to see if they will work for you then.
Hope this helps,
Shawn
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Self built custom
OS
64-bit Windows 11 Pro for Workstations
CPU
Intel i7-8700K OC'd to 5 GHz
Motherboard
ASUS ROG Maximus XI Formula Z390
Memory
64 GB (4x16GB) G.SKILL TridentZ RGB DDR4 3600 MHz
Graphics Card(s)
ASUS ROG-STRIX-GTX1080TI-O11G-GAMING
Sound Card
Integrated
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2 x Samsung Odyssey G7 27"
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2560x1440
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1TB Samsung 990 PRO M.2,
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Seasonic Prime Titanium 850W
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Thermaltake Core P3
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Corsair Hydro H115i
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Logitech wireless K800
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Logitech MX Master 4
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Google Chrome
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Logitech Z625 speaker system,
Logitech BRIO 4K Pro webcam,
HP Color LaserJet Pro MFP M477fdn,
APC SMART-UPS RT 1000 XL - SURT1000XLI,
Galaxy S23 Plus phone
I've done a bit of digging around for solutions to your issue. Here's the thing, C-Media never came out with a vista driver for CMI9880 which has been a major problem with many users like you.
There have been reports of some being able to use the old drivers for Win XP/2000 but nothing really sticks up as a good solution. They're reported limited functionality if any. I've seen download locations but can't verify their integrity and posting unverified sites is like shooting yourself in the foot.
Since there was no solid solution/workaround to make this sound card work for Vista, your chances of having this work for Windows 7 is close to nil.
If you have a shot at making it work for Windows 7, your best bet is try and use the Windows Driver Solution. Of course, there's always an option to buy a relatively cheap audio card that's vista compatible.