and in addition, the following additional steps may be required once the older wireless driver version has been installed or downgraded:
1. Install StandbyHelper to overcome the problem where disk activity due to Windows Indexing prevents the sleep request from completing (unless you choose to manually disable Windows Search Service):
http://babgvant.com/files/folders/random/entry16744.aspx
2. There is a lot of information about sleep problems and file and print sharing. Unticking this service for all active network adapters may be required if the sleep problem is still not solved.