A:Answer According to the Asus website:
http://www.asus.com/Motherboards/P5E/specifications/
Your motherboard has PCIe x16 I assume 1.0 based on the age.
Will the graphics card work? Yes, 2.0 is backwards compatible with 1.0 it will just run at a lower speed...
When you turn on your computer the motherboard will try to detect the graphics card use the first PCIe x16 slot and it should work.
The GT 210 is so old, but if you need a cheap card to browse the web, email and some flash then it should be ok..
I have a Pentium 4 running a Nvidia GT 610 and it just barely keep up with 720p video. It can't even do 1080p without stuttering.
Looking through graphics card, all these low end graphics card are horrendously overpriced.
I would go for the XFX - Radeon R5 220 Core Edition since it is cheaper $29.99 at bestbuy vs $35.99 for the GT 210 plus the R5 220 supports DirectX 11 native. Windows 7 uses DirectX 11.
Don't worry to much about the 400w power supply recommendation.
I run 3 hard drives + GT 610 + Pentium 4 3.0 Ghz on a 300w power supply and although the power supply does get a bit warm when everything is being used. I have not encounter any problems with normal regular use like web surfing and watching videos
