Screen capture videos

I’m having a hard time uploading quality videos to my site. I’m creating instructional, screen capture videos that depict things like Windows Explorer and various applications. I’ve tried several tools, like CamStudio with the lossless codec and Xvid encoder, and WM Capture with the MPEG-4 encoder. I can’t seem to get the H.264 to be recognized in any screen recorder program. I set everything to the highest quality, and I then convert the AVI files to MP4 and upload them to VideoPress. The videos look grainy and nothing like high def. Is there a well accepted method to make high quality screen capture videos? Thanks.