iMac won't read from USB or CD?!

[Blaqbetteh]

Hi guys.

I have an iMac 20" PowerPC G5 2.1GHz. I have a tiger disk but when I insert it, it starts loading and then I get a grey circle with a line through it (like a road sign.) I don't know what else to do? I have tried USB but I only have Snow Leopard on my USB,

Thank you guys for all your replies!

 

[simsaladimbamba]

Mac OS X 10.6 Snow Leopard will not install on your Mac, as 10.6 is only for Intel Macs and you have a PowerPC Mac, which uses a different architecture than Intel Macs.
Also PPC Macs will not boot from USB devices, unless one clones Mac OS X onto them.

The Tiger CD you have, is it the CD that came with the Mac or is it a Retail CD or a grey Restore CD from another Mac?