dell 3475 AMD A9-9425 running v slow

Hi, I am a newbie , just joining the community after searching the net for solution to the Inspiron 3475 very slow running problem.

I came accross the post by WhiteRabbitZeroZero about 3 years ago , solving the problem with a upgrade wifi adapter.  

Can anyone help me with the information of this upgrade wifi adaptor he was refering to and where to get it ?

Also, how can I contact "WhiteRabbitZeroZero"  to ask him for this information ?

It seems that all other remedies have minimal effects on the speed of the AIO.

PS:   I justed tried to reinstall windows 10 and I got the Dell logo on screen and a notice on the screen "windows startup struck a problem and need to reibstall windows 10"

Appreciate any help you can offer. Thanks