Feedback from inputs

Hi guys, this is my first post here. I'm new to Reaper, having just graduated from Audacity, and I seem to be missing a fundamental step somewhere. I can record through my cheapo Guitar Link using the provided drivers, but when I want to record from the line in or mic input on my computer I get noise on the track, even with nothing hooked up. When I turn the "Record Monitoring" on I get a feedback loop that immediately blows the track out until it self-mutes. I tried ASIO4All v2, WaveOut, and DirectSound, all with the same results. Is this a hardware problem or am I just not setting something up correctly? Thanks in advance, I'm loving Reaper so far.

What is it that you're trying to record? Are you using the basic soundcard which came with the computer?

Cool, I guess that's all I needed to know. I've already learned the hard way not to incrementally upgrade from the bottom-of-the-line product to the slightly less crappy one, so I suppose I'll just bide my time and work with what I got. I appreciate your help.

Ollie, we must have just posted at the same time. I'm not on a laptop, I'm using an apparently obsolete gaming tower with no built in mic. I was using the mic input with a mixer and a Korean Behringer knock-off.