The game's running pretty slowly for me now

[angryspacemidget]

I played Crusade 0.9.1 a few days ago on my computer and it was running very smoothly. I tried playing it again today on the same computer and it was just running at an awful speed. Is anyone able to help me? Here are my specs below:

Processor: AMD A4-5000 APU with Radeon(TM) HD Graphics 1.59 GHz
Installed memory (RAM): 6.00 GB (5.45 GB usable)
System Type: 64-bit Operating System, x64-based processor