Questions before answers...(I hope I have any answers, it sounds pretty weird)
1. Fonts are blurred on screen or in print or both?
2. Are fonts still blurred in another font in the same field (ie. if you change the font in that same field does the blur go away, if you change back to arial bold does the blur come back)?
3. Did the shop guys touch your monitor screen? (Yes, a joke...though perhaps not a funny one)
4. What FMP version and platform?
5. Reload your backup...is it blurred too?
6. Notice anything about arial bold in Word or XL or PPoint?