Continuing to try to fix things here.

My 770 has gotten more and more unstable, to the point it could not keep the connection long enough to load more than a page...

I tried to reset the 770's settings, using "control panel" and re-entered my wpa key manually. This has markedly improved things at first. I was able to keep connected for 10-20 minutes. I still got intermittent connection drops, though.

Then I restored my network settings from the MMC. The connection is still relatively stable, although the browser crashes on some pages.

A few notes in the case this problem is somewhat caused by corrupted settings:
-when I first set the 770 up, everything went fine, as far as I can recall.
-my wpa key is quite long (35 characters)
-when I first got my 770, I have added and removed 5 to 10 networks to the connectivity panel (I wanted to try things).

As a next step, I will restart the machine from scratch and re-enter all data manually. I hope it will make the machine usable again.