cars newest problem.

Car developed a new problem today took it for a bit of a blast and after about an hour battery light came on and it died:sad2:
Couldnt see anything wrong but the car would not start, turned out one of the fuses for the volvo loom (by the 2 relays) had blown swapped it for a good one and car fired up.
Now every time i put my foot down the battery light comes on and the engine jolts also it wont rev over 2k without doing it. I nursed the car home and will take a look asap.
Something has caused the fuse to blow but what? could it be alternator related? Any tests or things to look for would help me out. cheers fellas:D