using PSP7, (I assume the same would work in version 9?)...
With the picture open and active, from the colours menu choose increase colour depth, and choose 16 million colours. 9This wont colour anything but it enables colour to exist within the image...
Choose the "Colour replacer" tool, which in version 7 is a red, right facing arrow on a dark blue background.
In the colour pallet put the cursor on the left hand sample, pres ctl on the keyboard, keeping ctl pressed put the cursor, (looking like a small pipette), over the colour, (black in this case) on the photo that you want to replace, then release the ctl key.
double click on the right hand sample on the colour palette. This opens the dialogue box where you choose the colour you want to be the replacement, (red in your case).
Now all you do is "draw" over the area in question keeping the RIGHT mouse button clicked. This will replace colours in the left hand sample box with that in the right hand sample box.
Thanks for that. It's just not 'happening' though. I'm probably doing something wrong, but all I can achieve is colouring the white background red! Your instructions will need to be completely idiot proof! LOL
Care to try again in a monosyllabic, numbered step by step approach??!! ;-)
Use the selection tools to isolate the area you want to change, then choose edit/copy and then edit/paste as new layer. Make sure the pasted layer is in the correct place, select it in the layer palette and ensure that preserve transparency is on. Choose the flood fill tool and fill the layer with red. Only the selected area will fill. To have detail show through adjust the opacity in the layer palette.