Sorry if this is not an appropriate forum to ask this question. Can anyone give me some advice?

I've written some 2D DirectDraw based stuff on Win98 which runs really well but when I install it on Win2000 or WinXP, the frame rate drops to a crawl and runs really badly. This is on much faster computers with better graphics cards than mine as well.

Hardware acceleration and everything is enabled. Googled this issue till I'm blue in the face and can't find anything.

Again, sorry if this is the wrong place to ask but getting desperate. Ta.