And see how much to get it fixed. You've tried the usual but there are a few things that stand out.

8GB ram is too much for a dos based updater. Try it with the lowest amount of ram you can.

The 8800's are dying so use some other card if the update fails.

I'm going to assume you are using a small USB stick for the ROM file. I keep a 1GB stick around just for this.
Bob