Because I had the same thing today, I did following steps:
I logged out in Winamp, then I logged in again. Finally I saw the items in Winamp Storage inside of Winamp, which I didn't upload from the new install, but from the older (dead) install. In Local Library I saw 2 new tracks, which I got today from SoundCloud, not the other (older) items. I have cleared the Media Library and rescanned my folder "SabineKlare2" on D, I have logged out and in, at least I saw 7628 of 7630 items now. I have moved the 2 new files out and back, I have deleted them, I have copied them back from USB-Sticks, while Winamp was closed, Winamp is open again with 7630 items in Media Library, but not all of them are listed also in Local Library. Winamp says, many files are incompatible, and is removing them from Local Library. Winamp is not yet ready with this action. Maybe that could have been the reason, why I didn't see all items in Local Library the first time...
Winamp Cloud in Google Chrome shows a little bit more items of the new SABINEKLARE-PC now after reloading the page, no items yet in the playlists, but I will come back tomorrow and look again. I think, I will see also the other items soon...
Maybe I am not the only-one user of Winamp Cloud, who had to experience a reinstall of Windows...
If you also have problems, just try something around, like I myself did, You will always find a solution...
