Asus and Msi is ok but i would either get a gigabyte or evga board they are excellent for overclocking a core 2 duo. as for the videocard i would get at least a 7600GT or better if you plan on to play any of the latest games at reasonable graphics settings.
I would reccmend Counterstrike Source, FEAR, COD 1+2, Need For Speed Most Wanted and NFS carbon, Flatout 1+2 hitman blood money and i am sure there are more that i am missing to but these are some of the best games out there.
You probably have alot of spyware on your computer. Download Adaware SE at the bottom of this page in this link. Then if you have antivirus do a scan and clean up any viruses you may have. If you dont have a antivirus chose one from this link and install it...