You have a few options; one you can right click the file you want to open and select open with then set that as the default. You can go to change default programs and set your default programs there. You can also associate a file type to a particular program as well.
System Manufacturer/Model Number Custom built OS Windows 7 Ultimate 64 bit CPU AMD Phenom II X4 965 Black Edition Motherboard Gigabyte GA-MA790X-DS4 Memory GSkill 4 X 2 GB PC 8500 Graphics Card XFX Radeon HD 6790 D Sound Card On board RealTek HD Monitor(s) Displays Dual monitors:Samsung SyncMaster S20B300 Screen Resolution 1600 X 900
Keyboard Logitech G510 Mouse Razor DeathAdder PSU Ultra X4 750 watt fully modular Case Thermaltake Overseer RX 1 full tower Cooling Core-Contact 92 mm CPU Cooler Hard Drives Seagate Barracuda 1TB (primary)
Seagate Barracuda 2 X 320 GB Internet Speed 50/5 Mbps UL/DL Other Info Optical: Super Muliti DVD burner w/lightscribe, Hauppauge WinTV HVR-1800