I am not ignorant to the fact that this has probably been discussed before... just hasn't been discussed about "my" particular situation. I won't pretend to have a system loaded with Gigs and Gigs of RAM, HD space, and Mhz speed. It is a 2 year old Compaq Presario bought straight out of Radio Shack. It came loaded with some God-awful software that would not run correctly so I switched to the company's better software PowerDVD 2.55. I am still using it but.... There has been a couple of upgrades since. If I try running certain titles using 3.0, it acts like there is something running in the background slowing the system down... jumpy or lagging frames which is very irritating to watch and it locks up more so than not. I would hate to think what the 4.0 version would do but shouldn't software upgrades work "better" not worse on a system? I get the same effect using the 2.55 version, not as bad, if I don't reboot the system and shut down the Task Manager and Virus software first. Some movies play better than others depending on the compression ratios and action on the screen. If there are left to right fast action shots, it may be jerky. If there is some special effect shot, it may also play jerky... again, on some movies, not all. Any suggestions?