Hi,
I'm new to all this but have got a a couple of old servers mining plus my desktop. My problem is that rhminer is not finding my GPU. I've checked it's supported and it is (GTX 770).
When I ran the rhminer -list command all I got was CPU information and when trying to run using the GPU I get a message something like -gpu is an invalid command.
Does the card require a specific driver version? Any help would be much appreciated.

What rhminer version are you using? rhminer 1.2 release works with gpu.You may want to check the discord for help on gpu mining.
I'm using v 1.3.
I'll take a look at the discord too. Thanks.
1.3 is CPU only and you need the nvidia-cuda-toolkit installed under Linux for 1.2 to work. I am not sure about Windows. This is my old PC:
root@thebeast:~/rhminer# ./rhminer -list
rhminer v1.3 beta for CPU by polyminer1 (https://github.com/polyminer1/rhminer)
Build CPU Jan 11 2019 16:11:50
Donations : Pascal account 529692-23
Donations : Bitcoin address 19GfXGpRJfwcHPx2Nf8wHgMps8Eat1o4Jp
List of gpus and cpus:
CPU : Genuine Intel(R) CPU @ 2.40GHz
root@thebeast:~/rhminer# hashcat -I
hashcat (v5.1.0) starting...
OpenCL Info:
Platform ID #1
Vendor : NVIDIA Corporation
Name : NVIDIA CUDA
Version : OpenCL 1.2 CUDA 9.1.84
Device ID #1
Type : GPU
Vendor ID : 32
Vendor : NVIDIA Corporation
Name : GeForce GTX 1080 Ti
Version : OpenCL 1.2 CUDA
Processor(s) : 28
Clock : 1670
Memory : 2793/11175 MB allocatable
OpenCL Version : OpenCL C 1.2
Driver Version : 390.87
Platform ID #2
Vendor : The pocl project
Name : Portable Computing Language
Version : OpenCL 1.2 pocl 1.2 None+Asserts, LLVM 6.0.1, SLEEF, DISTRO, POCL_DEBUG
Device ID #2
Type : CPU
Vendor ID : 128
Vendor : GenuineIntel
Name : pthread-Genuine Intel(R) CPU @ 2.40GHz
Version : OpenCL 1.2 pocl HSTR: pthread-x86_64-pc-linux-gnu-haswell
Processor(s) : 24
Clock : 2700
Memory : 8192/30030 MB allocatable
OpenCL Version : OpenCL C 1.2 pocl
Driver Version : 1.2