can i replace core2 solo in laptop with core-i3/core-5???
Negative different sockets at the most you might be able to put a core 2 duo in its place but even that is a craps shoot since the duo processors have 1 less pin. Upgrading laptops CPU's aren't easy because usually the motherboards bios is only programmed to run with the CPU it came with sometimes it can run a different CPU if it was offered as an option with the laptop but there is no real concrete info on what can and cant work, but for sure an I3 or I5 will not work.
Only real option is just to get a new laptop since buying mobile CPU's are very expensive by themselves for the price you would pay for a CPU that might work you could buy a new laptop.