Unless it's a very old computer, your graphics card will be either PCIe (PCI Express) or AGP, and if it was bought within the last... Say, four and a half years, it will definitely be a PCIe setup for graphics with your other component cards running on a PCI bus. If it was a gaming computer sold post-2003ish it will also have a PCIe bus.
Yes PCI express 2.1 is backwards compatible
PCI Express was created in 2004.
PCI Express 2.0 x16.
PCI , AGP and PCI Express
The PCI Express x16 is intended to ultimately replace the AGP bus along with the PCI-X and the Conventional PCI.
You cannot use a 2.0 pci express card in a pci express slot because the technology is newer. For example: It would be like putting a playstation 3 game into a playstation 2 console.
pci express (PCIe)
PCI express uses a serial bus
PCI Express
You can find out by accessing your motherboard manufacturers page and looking up the specs
Yes, One PCI Express ×1
It should.