If, even after resetting it (hold down "home" + "sleep/wake" buttons for several seconds), you still can't delete the app (hold down finger on app until the "x" appears), then syncing may be your only option.
Then you're going to need to connect it to another computer, and restore your iPhone from a different computer.
Connecting it to another computer to have it sync will ask you to erase your iPhone. And it won't create a backup (because it wouldn't be
your iTunes library). So the only option I know of is to get that computer fixed... viruses suck, and are usually expensive to get rid of...
This is probably your next best option for your computer, at least.