khosrahudaikhulsi :
Actually I have a old pc case, that is mid tower.Now I want to buy rayzen processor and it's motherboard.But there in my present pc I have intel pentium4 processor and motherboard that have lga1151 socket.Actually I don't want to change my old case.I'll change everything without casing.Then without changing my old casing that had intel lga1151 socket motherboard, can I replace it by any amd rayzen processors and rayzen processor supported motherboard?
That only thing that should matter is the form factor of the case and motherboard. ATX, mATX and mITX are the most common three, so compare form factor and it should fit your case.
There is one area of exception: cases sold with systems built by OEM's such as Dell, HP, Acer, Lenovo are frequently proprietary. They can have design quirks, like oddly positioned mounting standoffs or a removeable board tray, that interfere with standard form factor motherboards.
Other things to watch for: the PSU may not be adequate for new system and drives may use PATA instead of SATA interconnects.