Window Update: This is the main reason behind the slow performance of your newly purchased laptop.
The laptop you purchased was likely built 6-7 months ago, So when you first time on the laptop, the system automatically starts the download and install all the Windows OS updates that have been released since. This task requires high CPU and disk use, and that is why your laptop working very slow for a few hours. The actual time depends on the internet speed and laptop task.
Bloatware: For revenue and promo, all brands give preinstalled third-party applications and software in the new laptop. So, when you turn on the device for the first time, you may notice there’s already a lot of software preloaded. This bloatware app slows down your computer. So when you turn on the laptop the first time, check out the pre-installed app before further use, and uninstall anything that you won’t want.
Slow HDD Drive and low RAM: HDD is now old technology, it is very slow for these days, for faster speed you definitely need SSD as your system drive. 4GB RAM is enough for light use, but for multitasking and heavy use, you need 8GB RAM on your system.