FFmpeg is not available for Audacity 1.2. You would have to extract the audio from the WMV files to WAV before Audacity 1.2 can import them.
Please be careful with XP. See https://forum.audacityteam.org/t/can-you-view-multiple-tracks-simultaneous/35313/3 All of your issues could potentially be caused by viruses eating your computer resources. Your machine might not be able to handle more than about a pop song length if you have many tracks, so you have no margin for other problems.
I would suggest you verify you have a clean machine by ensuring you have Service Pack 3 if you don’t have it already, then do an overnight virus scan.
Otherwise, the issues you mention mainly sound as though they could be related to your audio devices. After the virus check, please use Help > Audio Device Info… in 2.0.6 (or at least a late 1.3 version) and attach that information here. Please see How to attach files to forum posts.
Be aware that if you are using USB playback or recording devices, they must be connected to an empty USB port on the computer - connecting them to a USB hub could cause stalled playback or recording after a while.
If you are using the motherboard (built-in) audio or a PCI sound card, correct drivers (as up-to-date as possible for XP) are especially important. Please see Managing Computer Resources and Drivers - Audacity Wiki.
Gale