Norton Virus Scanner found 4 threats on my computer:

Adware.PowerScan (2 of them!)
Adware.P2PNetworking
Adware.SurfAccuracy

I clicked on the delete option, but it says "Delete failed." Now what?

The 4 items are probably in Norton's Quarantine folder. You can go into the folder and just delete them from the folder.

Cswchan, is probably right about the Quarantine folder...just in case you're not familiar with the "Quarantine" folder, you can open the Norton Anti-Virus Quarantine by clicking:

1. Start
2. Programs (Or All Programs)
3. Norton Anti-Virus (Sometimes shown as Symantec/ Norton Anti-Virus
4. Click on the "Quarantine" entry.

If the items are not listed in the Quarantine folder, you can try running the computer in Safe Mode and then running the Norton Anti-Virus and seeing if the delete will work. Sometimes an infected file is "running" and if so, Norton cannot delete or alter a running file. In Windows Safe mode, the infected file is usually not running, and so it can then be deleted.

I suggest you run Norton's "Live Update" manually before following the steps shown below. Run Live Update

If your Operating System is a Windows ME or higher, I suggest you uncheck the System Restore option before following the steps shown below. This is done to prevent a re-occurrence of the infected files through the System Restore process. Once the infected files have been removed, and your system restarted go back and reset the System Restore and then set a Restore Point. Windows ME System Restore

Windows XP System Restore

If you're not familiar with Safe Mode:

1. Shut down your computer.
2. Start your computer.
3. At the first screen, repeatedly press and release the F8 key. (tap on it)
4. When you see the Windows Start Menu, select the Safe Mode option by scrolling to it with your keyboard arrow keys.
5. When Safe Mode is highlighted, press the Enter key.

Depending on your Operating System, you may be asked what "Log-on" you want to use. If your normal log-on has administrator privileges, use that. If not, use the Administrator log-on, or any other log-on that does have administrator access.

Once Safe Mode is running, open and scan you system with the Norton Anti-Virus.

When the scan is complete, restart your computer. It will start in Normal Mode automatically if all is well.

Dwight

Norton 2004 Pro.
Based on the version that I still have running on 1 of my 7 machines... Open Norton Antivirus, 'Click' on 'Reports' on the left panel, 1st item is 'Quarantine', click on 'View Report', single left click on the 1st item to high-light, then click on the 'X' or 'Delete Item' or the 'Delete' button on your keyboard or select 'Delete' under the 'Action' tab. Repeat the steps as necessary to remove all the items in question. There may be other items in the 'Back-up' as well. Just click on the 'Backup' tab to reveal the items and they can now be deleted.
Close the opened windows and rerun the test. You can also try TrendMicro's online virus/spyware checker/remover available HERE It may ask to install an ActiveX item to check your computer. It works well and is quite thorough in it's testing. You may also want to install other virus programs. There are several which are available for FREE and do a wonderful job at keeping your computer virus free as well.
Here are a few links for you to try out....
AVG
AntiVir
Avast
Good Luck