|Tantrix, Right click your Desktop, choose Properties, under the Settings tab change the Color quality from 32 bit to 16 bit, click Apply/OK. Now go back and change the Color quality from 16 bit to 32 bit, click Apply/OK. This should rebuild the iconcache.db file and may correct the problem.|
You could also download Tweak UI at the link below. After you install it you'll find it in Start>Programs>Powertoys for Windows XP>Tweak UI. Open it and under Repair then choose Rebuild Icons.
That icon is a Windows icon and I doubt that the problem is virus/malware related but that your iconcache.db file got corrupted and needs to be rebuilt.