well, that computer is a bit old, but it may need some upgrades. I believe technically it is a 64 bit os, however I don't advise it, not on that old of a system. here are the system requirements for windows 7 http://windows.microsoft.com/systemrequirements
as you can see it recomends 1 gig of ram for 32 bit and 2 gigs of ram for 64 bit. You have 512 mb of ddr 400. its not much in todays world, and its slow. technically, since windows 7 isn't as memory intensive as vista, it
still run in theory, but your never going to obtain the full functionality of it, even if you do upgrade the ram to 2 gigs, though you would definetly see a difference.
Here is my advice: if you have XP, stick with it. unless you game, or watch hi def movies, XP will quite literally, do everything you need it to. It is still a solid OS. and perhaps save for a new system later on.
If you are insistent about windows 7, upgrade your Ram to at least 2 gigs. Believe me, you won't regret that, even if you stick with XP
If you don't wan't/can't afford more ram, go with windows 7 basic or home preium. It doesn't have a lot of the features that the fancier versions do which means your system will be able to handle it easier. A lot of those features would be a waste of money anyway, since they likely wont run fully or if they do will be slow.
Another option would to both upgrade the memory and upgrade to a dual core, such as a Pentium D. However, I cannot find a CPU support list online you will likely have to contact SONY to obtain a list. With a dual core and 2 gigs of ram, I can see 7 being very usable, without it, it will work decent, but I believe XP will work better in my humble opinion.
Primary system: Motherboard: ASUS M4A89GTD PRO/USB3, Processor: AMD Phenom II x4 945, Memory: 16 gigs of Patriot G2 DDR3 1600, Video: AMD Sapphire Nitro R9 380, Storage: 1 WD 500 gig HD, 1 Hitachi 500 gig HD, and Power supply: Coolermaster 750 watt, OS: Windows 10 64 bit.
Media Center: Motherboard: Gigabyte mp61p-S3, Processor: AMD Athlon 64 x2 6000+, Memory: 6 gigs Patriot DDR2 800, Video: Gigabyte GeForce GT730, Storage: 500 gig Hitachi, PSU: Seasonic M1211 620W full modular, OS: Windows 10.
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