Audacity sounds very tinny, recording with cassette player

I recently switched to a new Toshiba laptop with Windows 7. Previous laptop also had Windows 7. Audacity worked perfectly on that computer but with the new computer the recording is very tinny. I am using a cassette player with line in to the microphone jack of the laptop–same set up as the previous computer. I have tried various things with the Realtek audio system by looking at other posts but it still is quite tinny. I am only using it for transcribing talks so I can still mostly understand the words but not always–any help would be great. I have tried the MME with Speakers (realtek) and Mic in at front panel, also Windows Wasapi and direct sound but still the sound is the same.

You lucked out before. The new computer Mic-In is probably designed for a microphone…

…and nothing else. You can get around the lack of a stereo, high-level Line-In with a USB sound adapter such as a Behringer UCA202 like I have. They also make a UCA222 and other than the paint color, I never figured out the differences.

Please stay away from USB adapters such as this one:

They work perfectly, but they don’t have a stereo line-in, either. They just duplicate the connections you have already. I use mine to record telephone conversations with a special microphone.