jagged edges on videos!!!!!!

hey a;;
I found this section to be the best for my post, but if I am wrong pl tell me the right place to post. Ill do so immediately.

I have been using msi geforce 7300 gt for sometime now..I had to reinstall windows XP 2 weeks ago. That means all the drivers were to be installed again and all the settings went back to defaults(due to new installations). Before that my videos were smooth with amazing clarity and no jagged edges whatsoever. But after this I dont know what happened, no matter how much i play with the settings jagged edges simply refuse to go. Clarity has taken a massive hit. All the codecs that were installed have been installed again..
i am using forceware version 93.71. in the driver control panel no matter how much I play with image enhancement settings( edge enhancement, noise reduction etc.), nothing happens.... What is wrong with the system??? pl helpp!!!!

P.S. I usually dont play DVD files but AVI, mpeg etc.

thanx for the reply jaydeejohn. . The link says the obvious things which were already enabled...
I have even uninstalled klite codec pack.
please tell me what other issues might be causing this.....