Fret buzz

Will anybody visit this section of the board? Full disclosure, I basically never have.

Anyway, I have a now 20+ year old Ibanez S-Series (super thin, kind of cool) that I've always liked.  For the last however long (precise measure, I know) I've gotten some fret buzz on the first couple frets of especially the higher pitched strings, which makes several of them basically unplayable.  Last year for Christmas my wife took it in to a local music shop to be worked on, and I wasn't there for the explanation at pick-up, but they said they did what they could but it still had some, especially with heavy gauge strings for tuning down (I'm usually at C, standard tuning).  My related questions are legion, and as follow:

1) I DO want to play down-tuned -- is there any hope for this guitar?  Related, if I re-strung it with lighter strings and tuned to E, would that be likely to remedy the issue?  It would be for re-sale if it came to this, but it's a decent instrument and should be worth something in sale or trade if it's still good but just not for what I want.

2) If I do have to get into something different, are there things to look for in lower priced guitars that will be better or worse for excellent sounding down-tuned death metal type tones?  What makes a difference?  Particular pickup configuration?  Other things that I don't even know about?  Obviously I'm not a professional level guy or a guitar expert, and I would be interested in keeping costs down, which I'm sure the right lower-end guitar would suit me just fine, I just don't know how to find the right one.

Thank you for your help!

Couple different variables, like does the Guitar have a locking or standard nut, how familiar/comfortable are you with truss rod adjustments, and what string gauges you are using. 

It’s possible for the nut to have worn to the point that the string seat too low to accommodate the string travel of larger gauge strings.....MIGHT be fixable with some truss rod and bridge height adjustments, MIGHT be solved by replacing the nut.

there’s also the off chance that it’s a fretwear issue, where, say, frets 1-3 are low enough that you get buzz at 5, OR that whatever frets are causing the buzz have become slightly unseated over the years as the fretboard has expanded and contracted from temp and humidity. 

As far as “new Guitar” goes......the best thing you can do is determine a budget, and then get out there and play a bunch, even if you have to set aside a day to hit somewhere that has multiple stores in the area.  You never know what you might find.....

Thanks Exo -- I didn't really think anybody would see or respond to this!

I am no expert, but will just relate my own situation.

I bought a Japanese Strat off the rack (big mistake) way back when.

Upper frets buzzed, store did an adjustment for (I think) an extra $25. Never really helped. Since this guitar had a great locking tremolo and I basically just played chords tuned down to C (the guitar was basically a fun toy) I didn't worry too much about it.

Years later, decided not to invest any more money into it to get rid of fret buzzing when there were no guarantees it would even help.

Ended up selling the guitar for parts in 2014. Thankfully I got what I paid for it, although I was trying for more, but didn't get any bites at the higher prices.

Glad to be rid of it. No regrets about selling it, there are way better guitars out there.

Well, since this has seen another response, I suppose I'll at least provide an update, not that it's all so interesting.

I decided it was time for me to try a 7-string anyway, so I went the "new" guitar route and picked up a used Schecter.  Between that low b string and active pickups, it stinkin' GROWLS and I love it!  Pretty big difference between the old Ibanez s-series with the super thin, light body and the beastly 7-string with the full body and slightly longer scale neck, almost felt like playing a bass for a while, but I have been enjoying it for sure.  Can be seen in the latest video from my "Promotion Palace" post, not that I would particularly expect anybody to care as I'm basically a stranger talking about relatively low-end stuff, but there it is anyway!