Davidm said:
What does System File Checker (scf /scannow) do?
I've rebuilt my laptop using the manufcturers recovery disk, (WIn XP
SP1), installed laptop specif drivers, installed SP2 and SP3 using the
.exe files downloaded from the Microsoft website, then finally used
Windows Update (not automatic update) to download and install
everything since SP3 - took many hours!
I've had a couple of blue screen errors, and errors shwing in the
event logs, since doing all this, so wanted to sort this out before
installing applications etc.
I ran sfc /scannow, with the recovery CD in as instruected by sfc.
Will this not then put back old versions of files from the CD, or is
it smart enough to leave newer version in place, and how does it know
that they are the correct ones, or does it get updates online?
I've also ended up with some folders in C: with names like:
64C5DB82-98BC-4316-97F6-51216527892
HSNBYHDFHPIOEDHKASHIOAHEYSK
which are not marked as hidden or system folders.
Do I need to keep these?
sfc doesn't use anything outside the machine, that I could
see when I tested it.
It is smart enough to use files on the machine which have
come from updates. It would only use the CD for things that
have not been affected by updates.
Given that malware could affect just about anything on
the hard drive, sfc doesn't get a strong vote of confidence.
The files it might use from the CD, those will be good ones
and I don't have a problem with those. But for files which
arrived at the computer as updates, who is to say that any
of those files are currently "good" ?
*******
If it was my computer, I'd be in the Event Viewer now,
collecting all the error codes.
http://aumha.org/a/stop.htm
If the error or STOP code was the same for each one, then
that's a software problem (like, something incompatible,
wrong version, or whatever).
if the errors are randomly distributed, a 0xF1 error one
time, a 0x6C error another time, with no pattern to them,
that could be a RAM problem. In which case you could do
at least one full pass of memtest86+. Versions are available
for download, half way down this web page. You can make a CD
if you want. Lucky for me, my current machine still has a
floppy, and I keep a test floppy compatible with this machine,
nearby for this sort of thing.
http://www.memtest.org/
And that program is much better than other RAM testers, that
run on top of an OS. OS level testers, only test "free RAM",
and the kernel area is untested. Memtest86+ has relatively
good test coverage by comparison (only the bottom 1 megabyte
is untested, as it is reserved). But in terms of "confidence
building", a run with Prime95 stress test (mersenne.org/freesoft)
is often necessary to seal the deal. The advantage of memtest86+,
is you can relatively quickly spot a stuck-at fault on a
memory DIMM. But if the RAM "passes" the first test, you need
additional stress testing with Prime95 as proof the RAM is really
good. Prime95, being an OS level test, doesn't test the kernel
area, but if there is a marginal timing problem, the RAM that
passed in the memtest86+ testing, will have the odd failure
while Prime95 is running.
Also, you can load a different OS and do "comparison testing".
Say, for example, Windows is showing errors related to video
hardware, and you need a second opinion. If you boot a Linux
LiveCD (like perhaps Linux Mint, Mate interface), you may see
video errors there as well, and that would tend to point to
hardware, and not a duff Windows driver. This is how I
diagnosed a hardware design issue with my first PC,
namely flaky video (unbelievably crash prone - move the
mouse cursor on an idle desktop, and KABOOM).
I like to "prove" my hardware is good, before going on
an "sfc fishing trip".
Both Seagate and Western Digital, offer various diagnostic
packages for hard drives. I don't know whether Toshiba or
Hitachi do as well, but laptops might have different brands
than the ones I use on my desktop here. In any case,
there are read-only diagnostics, and read-write diagnostics,
if you suspect the hard drive is faulty. The purpose of the
diagnostics, is to obtain an "error code" which can accompany
a warranty claim. A hard drive will not be accepted for a
warranty claim, unless it "tests bad". And so the free test program
gives you a code if it is bad. So this doesn't say in so many
words, what the problem might be, but it can help you determine
that perhaps the drive needs to be swapped for one in better
shape.
I've used Seatools for DOS here, and it comes with FreeDOS
to boot the system (no need to provide your own DOS disk).
When I ran Seatools for Windows, it erased the config EEPROM
in my USB hard drive enclosure. So if you're going to use that
version, just remember to unplug the USB hard drives first
I was able to fix that little incident, with a repair utility
from Cypress Semi.
Paul
