I am having the same problem. I am running iTunes 10 on Windows Vista and I have an iPhone 4. I have uninstalled iTunes and Quicktime, run ccleaner, reinstalled iTunes, and I still get the problem. The iPhone shows up in My Computer, but not in iTunes. Here is the diagnostics report:
Microsoft Windows Vista x64 x64 Home Premium Edition Service Pack 2 (Build 6002)
TOSHIBA Satellite M305
iTunes 10.5.1.42
QuickTime not available
Apple Application Support 2.1.5
iPod Updater Library 10.0d2
CD Driver 2.2.0.1
CD Driver DLL 2.1.1.1
Apple Mobile Device 4.0.0.97
Apple Mobile Device Driver 1.57.0.0
Bonjour 3.0.0.10 (333.10)
Gracenote SDK 1.9.5.502
Gracenote MusicID 1.9.5.115
Gracenote Submit 1.9.5.143
Gracenote DSP 1.9.5.45
iTunes Serial Number 0035B29403A4A0A0
Current user is not an administrator.
The current local date and time is 2011-11-18 07:21:51.
iTunes is not running in safe mode.
WebKit accelerated compositing is enabled.
HDCP is not supported.
Core Media is supported.
Video Display Information
Intel Corporation, Mobile Intel(R) 4 Series Express Chipset Family
Intel Corporation, Mobile Intel(R) 4 Series Express Chipset Family
**** External Plug-ins Information ****
Plug-in Name: Aeon
Plug-in Loaded: Yes
Plug-in Version: 0.9.1
Plug-in File Version: Unknown
Plug-in Path: C:\Program Files (x86)\iTunes\Plug-ins\vis_Aeon.dll
**** Network Connectivity Tests ****
Network Adapter Information
Adapter Name: {B6BB589C-1E99-42D1-818E-FADC88A66B4D}
Description: Intel(R) Wireless WiFi Link 5100
IP Address: 192.168.1.120
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1
DHCP Enabled: Yes
DHCP Server: 192.168.1.1
Lease Obtained: Fri Nov 18 06:46:41 2011
Lease Expires: Sat Nov 19 06:46:41 2011
DNS Servers: 192.168.15.1
Adapter Name: {CDBD518E-7A32-4E0C-AD60-95A9F16E0242}
Description: Marvell Yukon 88E8040T PCI-E Fast Ethernet Controller
IP Address: 0.0.0.0
Subnet Mask: 0.0.0.0
Default Gateway: 0.0.0.0
DHCP Enabled: Yes
DHCP Server:
Lease Obtained: Wed Dec 31 16:00:00 1969
Lease Expires: Wed Dec 31 16:00:00 1969
DNS Servers:
Active Connection: LAN Connection
Connected: Yes
Online: Yes
Using Modem: No
Using LAN: Yes
Using Proxy: No
SSL 3.0 Support: Enabled
TLS 1.0 Support: Enabled
Firewall Information
Windows Firewall is on.
iTunes is NOT enabled in Windows Firewall.
Connection attempt to Apple web site was successful.
Connection attempt to browsing iTunes Store was successful.
Connection attempt to purchasing from iTunes Store was successful.
Connection attempt to iPhone activation server was successful.
Connection attempt to firmware update server was successful.
Connection attempt to Gracenote server was successful.
Last successful iTunes Store access was 2011-11-18 07:04:02.
**** CD/DVD Drive Tests ****
LowerFilters: PxHlpa64 (2.0.0.0),
UpperFilters: GEARAspiWDM (2.2.0.1),
D: TSSTcorp CDDVDW TS-L633P, Rev TO01
Audio CD in drive.
Found 9 songs on CD, playing time 76:28 on Audio CD.
Track 1, start time 00:02:00
Track 2, start time 06:58:26
Track 3, start time 21:04:12
Track 4, start time 28:07:33
Track 5, start time 43:38:05
Track 6, start time 47:09:07
Track 7, start time 49:35:63
Track 8, start time 59:49:68
Track 9, start time 68:08:56
Audio CD reading succeeded.
Get drive speed succeeded.
The drive CDR speeds are: 24.
The drive CDRW speeds are: 24.
The drive DVDR speeds are: 24.
The drive DVDRW speeds are: 24.
**** Device Connectivity Tests ****
iPodService 10.5.1.42 (x64) is currently running.
iTunesHelper 10.5.1.42 is currently running.
Apple Mobile Device service 3.3.0.0 is currently running.
Universal Serial Bus Controllers:
Intel(R) ICH9 Family USB Universal Host Controller - 2934. Device is working properly.
Intel(R) ICH9 Family USB Universal Host Controller - 2935. Device is working properly.
Intel(R) ICH9 Family USB Universal Host Controller - 2936. Device is working properly.
Intel(R) ICH9 Family USB Universal Host Controller - 2937. Device is working properly.
Intel(R) ICH9 Family USB Universal Host Controller - 2938. Device is working properly.
Intel(R) ICH9 Family USB Universal Host Controller - 2939. Device is working properly.
Intel(R) ICH9 Family USB2 Enhanced Host Controller - 293A. Device is working properly.
Intel(R) ICH9 Family USB2 Enhanced Host Controller - 293C. Device is working properly.
FireWire (IEEE 1394) Host Controllers:
OHCI Compliant IEEE 1394 Host Controller. Device is working properly.
Most Recent Devices Not Currently Connected:
iPod nano (3rd Generation) running firmware version 1.1.3
Serial Number: 6U742DHGYXT
iPhone 4 (GSM) running firmware version 5.0.1
Serial Number: 870224UDA4T
**** Device Sync Tests ****
No iPod, iPhone, or iPad found.