firefighter

I have access to an unused computer once every couple weeks and i would like to be able to access it remotely in order to take advantage of its internet connection.

however i would prefer not to leave it running the whole time, while the perfect solution would be if it were possible to turn the computer off and on remotely i doubt this is possible, what other options are on offer?

is it possible to wake a computer up from standby via remote access or would it need to be running straight for weeks at a time, if so what are the risks of this?

Thanks for your help.