Where to get a pytorch version with cuda 7.5

I know pytorch support cuda 7.5, but try to install online, it failed

my platform is win10 + anaconda3,not in linux

CUDA 7.5 was used when PyTorch 0.4.1 was released and if I’m not mistaken, no Windows binaries were built for this old release.
Your best bet would thus be to check out this legacy release and build from source.
I would generally recommend to stick to the latest release.

My laptop’s GPU is nVIDIA GeForceGT 650M,whic is very old, does the latest CUDA works for this old GPU ?

CUDA 10 would support it, but I think that the lowest compute capability supported by PyTorch is sm_35, so you wouldn’t be able to build it for your device. In that case you could either try to use remove GPUs (e.g. via Colab) or indeed build an old release from source.