That card has been used many many times in many many PCs. HOWEVER I find many of today's owners unable to install drivers and will call such an incompatibility.
Why did you get the 512MB model when the 1GB is usually 29 bucks?
I bought one of these http://uk.ts.fujitsu.com/rl/servicesupport/techsupport/professionalpc/ESPRIMO/E/EsprimoE5710.htm secondhand a while back to basically use as a htpc extender for the bedroom. While its powerful enough for this purpose, the onboard graphics are not up to pushing xbmc/wmc smoothly (it will do it but its clunky) I bought a Radeon HD 5450 HyperMemory - HDMI - 512 MB GDDR3 - PCI-Express 2.0 (11166-08-20R) but the machine did not not like it, presumably its not compatible with the motherboard.
Can anyone tell me what type of card I need and where I might be able to get my hands on one? many thanks.