In reply to anyone with the same problem as AnneHglnd :
If all else fails:
... and you desperately want to fix and run the 30sec. experience index test, which rates your computer's performance average between 1 and 8 (you can do this yourself by looking at your computer's purchase receipt, which gives a far better indication of the performance score it rates), you could do a repair install of W7 if you have a W7 disk.
Alternatively, you could completely ignore this stupid index feature! :-)