You may if you significantly increase your RAM to 4gigs from 2gigs but it probably isn't worth the effort, wait until Windows 7 is released and consider upgrading then. 32bit OSes are limited to 4gigs of RAM; that includes physical sticks as well as video card combined, so going to 3 gigs may be an option to maximize your system and help performance. And I really would suggest going to an E8400 at the very least; no problems at all with 720p material not even a hiccup. You can get an E8400 for about $170 USD.
Core2Duo E8400 (@ 3.0), 8gigs of Mushkin, Vista Home Premium SP2 64bit, 2.5 TB of Space, Wired to Linksys WRT54G wired to 80GB MGS4 PS3 on Sharp 32" 720p LCD TV