Please share about freeze or unsync trouble on Win7 x64 or Intel Chipset. iPhone 3G

I occurred the sync trouble, it started from current Win7(x64) PC.
Please give & share me(us) your trouble shooting information.
My Environment;
Mother board: ASUS P7P55D EVO
CPU: Intel iCore5
Memory: ...(forgotten) 4GB
OS: Windows 7 x64 Ultimate JPN
iPhone: 3G
Symptoms;
Cannot sync with iTune (ver 10.1)
Trouble shoot;
About PC or OS;
Windows XP x86 with other hardware models can sync the iPhone.Mac-mini can sync the iPhone.
USB;
I change to connect other USB port from the mother board.
And I can sync. But at last, iTune 10.1 suggested me to update iOS 4.2.1.
I agree that, cant update that.(f u ck)
Apple store;
He said, This iPhone is okay. only.
He is funny guy.Please inform me about your knowledge and any good forum URLs.
And please help him. He will get fired.
Win7(ByMyself),mac-mini Windows 7 P55 Intel Express