Welcome to the forums, newcomer!
i also have this power supply from intex (Intex IT-25F2) 600w 20-4 pins
That is a horrible PSU unless you want to ruin everything that it's hooked up to.
i have a motherboard from gigabyte (GA-F2A55M-DS2) but this motherboard requires 24+8 pins power supply, will my power supply work?
I wouldn't call that Intex unit a PSU, more like an expensive paperweight.
yes i know its old but that's what i can only buy
If what you're saying is true, then you should invest in a reliably built PSU to protect the rest of your investments.
what power supply should i use?
Where are you located? What is your budget for a PSU purchase? What is your preferred site for your PSU purchase?
Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
Chassis:
OS:
Monitor:
BIOS version for your motherboard at this moment of time.
and coupled with the answers for the questions above, we can move forward with suggestions.