Download Youtube Windows 7 [exclusive] Link
I finally gave up trying to run software on Win7 directly. Instead, I installed Ubuntu (dual boot) on the same hardware. I download the videos in Linux (where everything works perfectly), save them to an NTFS partition, and then boot back into Windows 7 to watch them.
JDownloader 2 is heavy on RAM (500MB+). Not ideal for low-spec Windows 7 netbooks. download youtube windows 7
directly from the browser's address bar, Windows 7 was a bit of a time capsule I finally gave up trying to run software on Win7 directly