Not sure if my Dell Inspiron 530 can handle this graphics card. Click Here My computer has a 300w power supply and I'm not sure how many PCI slots or whatever it is it has.

Dell has a pretty good site for support and documentation. here is the link to their site with information about the specs: http://support.dell.com/support/edocs/systems/inspd530/en/OM/HTML/appendix.htm

From there you can see the computer supports PCI Express, but no mention of 2.0. A further search on their site reveals a question on their forum similar to yours:
http://en.community.dell.com/support-forums/desktop/f/3515/t/19329902.aspx

In any event...you should be OK. The PCI Express 2.0 is backwards compatible with the PCI x16 1.0 and 1.1 slot motherboards. However, PCI-e 2.0 cards on 1.1 and 1.0 motherboards will not be able to run at their max capacity.

Read more: http://wiki.answers.com/Q/Will_pci_express_2.0_work_with_pci_express_x16_motherboards#ixzz1wOU2oJVT

Thanks, also, one more question. Would this be ok for normal gaming? Not softcore or hardcore gaming, but in between?

and, could it run Arma II: Operation Arrowhead?