What do I have to do to go back to dying my gray hair blonde?

You'll probably need to get the brown out, yes. Another thing you could do is -- and I'm unsure about how this would look or quite how you'd pull it off -- but maybe transition the color. You don't say how long your hair is. If it's rather short (e. g. above your shoulders), the transition thing might work. If it's longer than that, you will probably need to strip the dye completely off as it'll be a while before your roots have grown out so much that the blonde would become truly prominent again.

having done hair for a very long time, I have a few questions..

what is your hair type? Is it thin? thick? curly? oily? dry? brittle?...
what is your ethnicity? ( yes that can play into hair types)

is the brown semi-perm?
How are you putting it in? Is this a box from the store? ( a basic color deposit) or are you pulling or lightning your hair BEFORE you add color?

Are you using stripping shampoo?

Thanks for replies. To answer your questions, Shewolfnm, my hair type is straight, medium thickness (not super-fine, definitely not coarse, but a lot of it), fairly healthy, though scalp can be on oily side. I am caucasian. My hair is naturally very dark brown, and yes, the brown I've been putting in is semi-permanent. I've been using Garnier HerbaShine and not doing anything else. Same thing, when I was doing blonde, I would just put a medium neutral Natural Instincts blonde in, and I was fairly satisfied with the results. I've heard that some the other semi-perm brands are better for gray coverage, and Natural instincts changed their formula, so I'll be using something else, like Loreal Healthy Look.

I did buy a box of that Clairol Color Oops color remover, but I've heard it's a pain to use properly. I guess you have to rinse your hair for thirty minutes or something, but I will do it if that's what it takes. I am not willing to go to a salon or bleach. But I don't want to be walking around with these roots either. I'm not familiar with stripping shampoos. Do I get it at a beauty supply store and do they work? I shampoo my hair every other day with Denorex 2 in 1 dandruff shampoo.

Sorry it's so long and TMI. I really appreciate any info and help I can get. Thank you so much.

I haven't posted my question on any other forums, but after answering your questions, I'm curious to see what your response would be. Hope to hear from you! Thanks