You don't say what operating system, but if windows 7 or 8 I'd suggest a fast ssd for the operating system, and keep the data on the other drive. I'd also suggest a 64 bit os and more ram 8gb minimum, especially if you're using Lightroom or Photoshop. The more layers you use in Photoshop the more ram is better.
Crucial 550 mb read & write 500gb ssd sea now around £170 and make a huge difference, or about £85 for the 240gb.
If you're using Lightroom, check out the performance hints about where to put the cache, database etc
Lastly, if you haven't usb3, consider a USB 3 card and flash card reader to speed up,import time.
If you don't want to spend money, look at the disk system and ensure no error. Run chkdsk, check defragmentation, check what're grams and applications you have loading at startup and consuming your working memory. Things like Adobe, google updater, flash updater, office startup etc all like to add themselves to your startup. If windows 7 run msconfig and look at what your have at startup.
Also go into scheduled tasks and see what's in there, then make an intelligent decision if you need those running. You'll be amazed at how much faster your PC will seem.