Improve performance on an older pc

I have a Dell Dimension 9150 that's running XP. I do have a lot of programs including Creative Suite cs3 for designing. The computer is at least 5 years old and I'm wondering if I should just get a new one or if I can improve the performance of this one. It used to be able to run Photoshop and Chrome without any issues but over the past 7 months it has gotten slower and crashed several times.
Can you give me some recommendations on what I can do to improve the pc to what it once was?
Here are some specs:
Windows XP Home - 5.1.2600
RAM 2 GB
Intel x86 family Model 4 Stepping 4

Now sure what else you'd need or where to start.

Thanks