Okay, so here's how to run a hack on your computer. First, you need 4 things:
-Visual Boy Advance
-Lunar IPS (LIPS)
-A clean Firered ROM
-The hack you want to play (it should be a .ips file)
The first two you can just search and they'll come up. I'm pretty sure you've at least heard of LIPS, and I'm sure you've heard of VBA. The third you'll have to find yourself, I'm not allowed to direct you to one from here.
Anyway, open LIPS, click the button that says "apply patch." Select the IPS file for the hack you want to use, then select the clean FireRed Rom (keep a copy of the ROM so that you can use it for other hacks). Finally, open the modified ROM with Visual Boy Advance, and it should run the hack.
Anyway, hope this helps!