EOS Utility does not recoganize Canon Rebel Xti

Skip the software, use a card reader/writer.
No software necessary.
Buy a card reader at any store such as Walmart, Officemax, Best Buy, and so on.

try doing a system restore to yesterday and then try installing the disk again.

You can do the restore from control panel and inside "Performance and Maintenance"

Please let me know it this still doesn't work and we can go from there in finding a way.

thanks

Use a card reader to download your pics.

Sounds normal. You could get a faster computer. I like using a  USB card reader. 

I am not sure about this matter but it seems there is a problem with your new computer. it might not recognize the usb cable.
try to plug your camera in another USB port and try again.

The EOS Digital Rebel, EOS Digital Rebel XT and EOS Digital Rebel XTi do not support stamping the date and time on the image.

It is not possible to record the date and time as part of the image at the time the picture is taken. However, the date and time is captured in the EXIF information of the image at the point of capture. It is possible to print the image with the date and time via printing software. Please see the documentation for the software package that you use for printing images for the proper procedure.

Having same issue as above - I thought it was my cable so I ordered a new one. The camera attempts to 'speak' to the pc - and then the Windows box pops up not recognising the USB installed device....I also uninstalled and reloaded the Canon software (had camera for 18 months and only started this rubbish a month back) - was about to re-laod my entire PC - thankfully I saw it was not only me.

Will send mine in for a Firmware update / service.

try vista ultimate and download a softaware for your camera compatible for vista

edmerk:
In your case it seems like the software is the problem, try uninstalling it completly and reinstalling it back after a restart of your machine, also check this:
http://www.microsoft.com/windowsxp/using/digitalphotography/takeit/transfer.mspx
If this does not solve the problem then try using any other software for downloading pics from your camera or simply use the windows built in feature like:
Going to my computer, and check if you can see your camera drive there and simply copying and pasting from there. (see if this helps you).
I hope it helps you!

Seems to be a common problem with the XTi. Some say it's designed to underexpose to avoid washing out the bright parts of scene. Personally I found it a pita. I had to PhotoShop each shot.So I sent it back to the repair facility. They re-calibrated it. Now it works fine.