My laptop Acer Aspire V3- 571G became slow and gets hot on the left hand side underneath after upgrading to Windows 10. Is it because my graphic card GE Force GT640M is not compatible to Windows 10? what do I do about it?
Compatibility with whatever software or OS you are using would not make it get hot.
However, problems with a GPU, CPU, fan, etc., could.
First you need to monitor the temps for the laptop to see exactly what is overheating and when it is happening. Is it all the time? When running certain programs? Playing certain games? Etc. This will give you a better idea of what is going on.