HELP ME PLEASE !

[lucasier]

Hi everyone. I am a newby and have just purchased a 2005 Turbo Diesel. It has been sitting at a workshop for two weeks now with the following problems.

1. Alternator went dead (surprise surprise). I replaced both battery and alternator.
2. Computers went down, had a technition reflash and restore the electronics and clear all trouble codes and re test after test drive.

The car did go into limp mode when the power was going low but prior to that the car was going through all gears and plenty of power.

Ever since the alternator was replaced, the car feels like it has only got 10% of the power and almost stops even under full throttle on an incline.
I can hear the turbo under boost but no power output. I have just done a service inclinding Fuel, Oil and Air Filters and oil change to no avail.

The technition I used is a smart man and swears its not an electrical fault and is mechanical. Is this co incidence it stuffed up just after re assembling the alternator or can there be another cause ie blockage somewhere or incorrect installation of belt (if thats possible).

Any help or ideas on the problem would be appreciated as I already went over my head on the purchase and now the repair bills are stacking up and I havent even driven it for more than a day. (purchased at auction). It is not under warranty.