IS it just on the PSU wire? Are there any other indications of burning? It might be that your GFX card is Fooked and blown a capacitor or something (complete guess BTW) as i would expect more than just scorth marks on the OUTSIDE(?) of the plastic casing.
Are there any exposed wires on the PSU cable either? Can you try another PSU wire or Graphics card to see what the culprit is?
If its the Graphics card, i have a 9800 Pro for 100 quid if you want one
