Can I use old versios of Adobe Premiere Pro (2015) on my laptop with Windows 10?

Actually, 8 GB is the official minimum requirement for Adobe Premiere Pro 2022. 16 GB or more is the recommended minimum.

With that said, if your laptop has only 8 GB and relies solely on integrated Intel or AMD on-CPU graphics, you will have significantly less RAM available for Premiere Pro than the installed amount because all on-CPU integrated graphics processors steal some system RAM for itself, and that borrowed RAM becomes completely unavailable for programs until the IGP processing is finished. This may force-disable GPU acceleration and/or GPGPU decoding and/or encoding, forcing everything onto the CPU portion of the chip. And then, you will be at the mercy of your CPU (which may be seriously underpowered for video editing).

2015 is no longer available. You could try 2018 or 2019, but you do need a subscription.

Adobe CC 2018 Direct Download Links: Creative Cloud 2018 Release | ProDesignTools 

Adobe CC 2019 Direct Download Links | ProDesignTools