I have a PC running Windows 7 and a 4 channel external ASIO audio card. I thought I could record line in with Audacity but it doesn't suport ASIO. What other options do I have? I need a simple lightweight app to do the job.
First, Audacity does support ASIO, it just can't include it in binary releases because the Steinberg license is GPL-incompatible. But if you build Audacity and the ASIO SDK from source, that should work fine.
Alternatively, you can use a different DAW. Reaper is very flexible, supports ASIO and a bunch of other non-free standards out of the box, and is still very lightweight – perhaps not quite as lightweight as Audacity, but still so small that it can't possibly be a problem on a system that can afford running Windows. It isn't free software, but probably as close to freedom as proprietary closed-source software can get.