A laptop of that age should not have any trouble with the kinds of things you’re doing, so it’s probably more of a hardware issue than a software one, unless some rogue process is eating up your CPU. You probably don’t need a lightweight distro (unless you prefer to keep things extra-light) and if it’s a hardware issue installing one may not help. So, as others have said here, first check the running processes for anything odd, then repaste it and blow out the dust.