Hi,
I just downloaded the latest version for Windows 64bit (v0.8.8.2) and pasted it over my older v0.8.5 install.
I left everything else in the folder, including my wallet.bin and wallet.bin.keys files (which I called "mein_wallet.bin" and "mein_wallet.bin.keys").
After starting bitmonerod.exe it synchronizes with the network for some time till it tells me that it is synchronized and I can start up simplewallet.exe
When I do, it synchronizes as well until it reaches the last block and shuts itself down with out warning. Restarting simplewallet.exe yields the same result.
This is the simplewallet.log print out:
2014-Aug-31 14:41:37.393025 bitmonero wallet v0.8.8.2(0.1-g1b8a68f)
2014-Aug-31 14:42:19.646442 bitmonero wallet v0.8.8.2(0.1-g1b8a68f)
2014-Aug-31 14:42:22.131584 ERROR ..\..\src\wallet\wallet2.cpp:552 e || !exists. THROW EXCEPTION: error::file_not_found
2014-Aug-31 14:42:22.132584 ..\..\src\wallet\wallet2.cpp:552:struct tools::error::file_error_base<1>: file not found "mein_wallet.bin.keys"
2014-Aug-31 14:42:22.132584 Error: failed to load wallet: file not found "mein_wallet.bin.keys"
2014-Aug-31 14:42:22.135584 ERROR ..\..\src\simplewallet\simplewallet.cpp:387 could not open account
2014-Aug-31 14:42:22.135584 ERROR ..\..\src\simplewallet\simplewallet.cpp:1199 Failed to initialize wallet