ITunes installation problem

Hello,

I just bought a new iPod Nano,but I deleted iTunes awhile ago. However, the program still exists on my computer, but it doesn't appear when I search for it. Whenever I try to delete the old iTunes, this message pops up:
The feature you are trying to use is on a network that is unavailable. Click OK to try again, or enter an alternate path to a folder containing the installation package 'iTunes.msi' in the box below.
Then:
The path 'C:\DOCUME~1\Ruhi\LOCALS~1\Temp\IXP780.TMP\iTunes.msi' cannot be found. Verify you have access to this location and try again, or try to find the installation package 'iTunes.msi' in a folder from which you can install the product iTunes

Please, I need help, and I need it NOW!!!