Your processor, hard drive, etc. are good enough to run Vista well. However, with just 512MB of RAM you are at the bare minimum recommended amount, so it would be a stretch. To make matters worse, your computer has integrated graphics, which is basically a chip on the motherboard that simulates a 'true' graphics card and utilizes RAM since it lacks dedicated memory. Thus, once integrated graphics takes its chunk out (128MB-256MB), you have just 256MB-384MB to work with, far less than the minimum recommendation.
Now, that doesn't mean you can't run Vista. However, gaming, playing videos, and running multiple programs at once would all cause serious performance hits. If you were to upgrade to Vista the first recommendation I would make is double the RAM to 1GB. (From your computer's specs, you can just purchase two sticks of 256MB DDR400 (PC3200) DDR SDRAM and insert them along side what you already have.) Then, if you would like better graphical performance, installing a true graphics card would be an optional upgrade. the RAM is almost mandatory, though, if you wish to have decent performance.
Hope this helps,
John
i have a compaq presario computer. it has AMD sempron, sr1903wm. it says on the computer that it was designed for windows xp, but is compatible with vista. my question is which one will work the best on my computer.
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic