Free fixes first: disable unnecessary startup programs (Task Manager > Startup tab), run Disk Cleanup, and scan for malware. If it's still sluggish, the single biggest real-world improvement for an old machine is swapping a mechanical hard drive for an SSD — it's a night-and-day difference in boot and load times, usually more impactful than adding RAM.

先做免费的：任务管理器→启动标签禁用不必要的开机程序，跑一遍磁盘清理，扫一遍恶意软件。如果还是很卡，对老电脑来说最立竿见影的升级其实是把机械硬盘换成SSD——开机和加载速度的提升是质的飞跃，通常比加内存更有效。