Vista - WEI gone nuts

Hi all, first post here, hope you don't mind about my low skills.
My machine: Core2 Duo E6600, RAM 2GB, HDD 320GB, Vista HP 32+SP1.
To install SP1 I did a fresh install on my machine and all went good, but
the WEI windows experience index seems not to think so: since when I
installed the OS again, the WEI detects a change in hardware which actually
is not and asks me to update the scores, but when I try to do it , here an
error message comes up , at nearly 90% of testing.
Did a winsat formal -v through command line, I'll quote here the tests that
weren't completed

Here's the log
4423455 (3368) - winsat\main.cpp:1161: > Running Assessment: media '-input
{winsatencode.wmv} -encode {winsat.prx} -v'
4423673 (3368) - winsat\main.cpp:1430: > Assessment FAILED due to an error


4488913 (3368) - winsat\main.cpp:1161: > Running Assessment: disk '-flush -n
0 -v'
4489084 (3368) - winsat\main.cpp:1430: > Assessment FAILED due to an error


And here's what winsat formal -v output

Requesting a file of size 536870912 located at physical offset 0x10000
Error: Failed to properly assess the disk. The drive cannot locate a
specific area or track on the disk .

Now I followed also the tip suggested here
http://forums.microsoft.com/technet/...&tf=0&pageid=1

But the result was neither that a new scoring was possible nor I could have
a score anymore. Is there anything that I can look at to fix this?
Thx for your care!
M