I have Windows 64bit and it runs the Beta wallet fine - I did have a small issue on first install - this was due to an old beta folder so I deleted it.
Roaming. This folder (%appdata%) contains data that can move with your user profile from PC to PC—like when you’re on a domain—because this data has the ability to sync with a server. For example, if you sign in to a different PC on a domain, your web browser favorites or bookmarks will be available.
I had the same problem the other day - but fixed it
So I went to my roaming folder %appdata% and deleted the NavajoAnonbeta folder and re-installed and works fine
mate please dont touch the summercoin2 folder this is where your hard earned saved up NAV/BTC is
My 2.05 wallet crashes alot in windows 64bit but thats being fixed in next release.
The old 2.04 wallet works great in windows 64bit but of courses does not contain all the bug fixes and stakeing fixes like the 2.05 wallet does.
Lots to look forward 2
I have a top of the line gamers rig Windows 64bit and run AMD Mantle Battlefield 4 preety sick so I like 64bit.