To all who tried to help:
I ended up sending back my Athlon 64 Winchester, that I had damaged while
trying it to work in 5(!) different boards,(two of them ABITS) and got a
Clawhammer core instead.
Installing was a breeze, and now everything is absolutely perfect! The PSU
that Wes Newell recommended is very good, so quiet.
Thanks also to Richard Hopkins!
http://store.mrtechus.com/60ulapatxcop.html, and only $18.
So, I ended up with the ASUS after all. I have ordered better and faster
RAM, DDR Corsair 400, and then I will be completely happy. Until I get the
urge to build a new system!
Thanks again!
Sonja