Displaying, zoom Problems

Greets,
I have developed an application that I use to display some images (school project). It worked fine under Windows98 but recently, they moved us under Windows 2000. Everything works fine except when I zoom in. The image gets blurry, sometimes (in black and gray) black lines are introduced, or color are changed (i.e. light green becomes dark green). I updated my video card drivers but nothing changed. If I zoom out again, the image is intact. I suspect this function to be a part of my problem ...

lngResult = StretchBlt(Me.PictureViewPort.hdc, _
-Me.HScroll.Value, _
-Me.VScroll.Value, _
srcewid * ZoomVal, _
srcehgt * ZoomVal, _
hdcNew, _
0, 0, _
srcewid, _
srcehgt, _
SRCCOPY)

PictureViewPort is the control I'm using, the size is giving with the scrollbar and srcewid and screght are the size of my image * the value of my zoom.

Like I said it worked perfect under 98 and its very slow and buggy under 2000. Anyone have an idea ? Maybe this function aint supported ?

Thanks for your time.

Just looked stretchblt up but the only warning about using it is that it is very processor hungry. I know I had so many problems with older games wen i switched to 2000 that i went straight back to 98 but thats all i know. Hope it helps

Dan