wireless modem help?

my pc is about 3 years old. will it work with a wireless modem or will i need a cable to actually connect it to the modem?

Most wireless modem/routers i've seen also let you connect via a wired route as well.. in fact you normally have to connect via wire when you configure them before being able to do it wirelesly

You need an ethernet port on your PC to be able to connect to a modem/router with a wire.. the modem/router should come with the wire attached (all the ones i have ever bought have done).. you just need to know if you have an ethernet port in your PC, most laptops i've seen come with them built in, with a desktop you'll have to look round the back and see if you've got one.