Well, I was one of the many with sync issues, mine was that the device would be recognized but would be stuck on "Connecting" in the ActiveSync program. Below are my details and what I did to fix it.

Windows 2000 XP4
McAfee Personal Firewall
Cisco Systems VPN Client
Active Sync 4.1
Axim X51V with A00 hardware and A04 Flash ROM
USB 1.1 - No hub
Using Cradle to sync
Office XP

After trying to uninstall everything that might be messing with ActiveSync I read a different thread about the Cisco Systems VPN Client stopping communication with the device. If you have this on your machine try opening it without connecting and turning OFF the Statefull Firewall. Restart your machine and then try synching.

I now have everything running again and it syncs, albeit not perfectly, but oh well. It had troubles synching with my calendar but if you run the Repair (scanpst.exe) it might fix it. Now my Axim will sync most of the time, maybe I have to pull it off and put it back on etc. but I can live with that.

I also have not had any turn on or off issues.

If I forgot something please post and I will try to help.

I am having problem too....I just unplug the usb and plug in again until it's ok. Works ok but troublesome....LOL ...