Deciding what to upgrade on your PC depends on your specific needs and budget. Here are some suggestions based on the search results:

• System memory/storage (HDD or SSD): If your computer is running slow, upgrading your system memory or storage can help improve performance. If you have a hard disk drive (HDD), consider upgrading to a solid-state drive (SSD) for faster boot times and application loading.

• Main memory: If you frequently run memory-intensive applications, such as video editing software or virtual machines, upgrading your main memory (RAM) can help improve performance.

• Graphics card: If you use your computer for gaming or graphic design, upgrading your graphics card can help improve performance and allow you to run more demanding applications.

• Processor: If your computer is running slow and you have already upgraded your memory and storage, upgrading your processor (CPU) can help improve performance.

• CPU cooler and fan: If you have upgraded your processor and notice that your computer is running hot, consider upgrading your CPU cooler and fan to prevent overheating.

When deciding whether to upgrade your PC or buy a new one, consider the cost and benefits of each option. Upgrading a single component can be cheaper than buying a new computer, but if your PC is outdated and lacks essential features, buying a new one may be the more sensible solution in the long run.