This tip is based on a complete misunderstanding of how prefetch works. Prefetch does NOT preload applications or any portion of them at boot time. Prefetch files are referenced only after application launch has been initiated. Unused or rarely used entries will have virtually no impact on performance. Manual deletion of these files will impair performance and has no benefits. In any event the prefetch folder is self cleaning after 128 entries. This has been extensively tested.

References:
http://home.comcast.net/~SupportCD/XPMyths.html

Larry Miller
Microsoft MCSA

good advice anyway though

*roll*

ALWAYS DO A DISK CHECK BEFORE A DEFRAG,

Method Below:

Error checking your Hard Disk (Thorough Check)
(use this Method a minimum of once per month
or straight after a unscheduled re-boot or system crash)
a. Open “My Computer”

b. Right Click over “Local Drive C:” or its Icon
(or the Hard Disk you’re checking, e.g. “Local Drive E:”)

c. Left Click on “Properties” at the bottom of the pop-up menu when the “Properties” window opens

d. Left Click on the “Tools” tab near the top

e. Then Left Click “Check now…” in the Error-checking section when the small new window opens

f. Put a “tick” in both boxes:
“tick” (Automatically fix file system errors)
“tick” (Scan for and attempt recovery of bad sectors)

(Only “tick” Automatically fix file system errors to run the Standard Check, this will only take about 5-20 minutes)

g. and Left Click on “Start” on the small window

h. Another message will appear, Left Click on “Yes”

(the message says you can only do a thorough Hard Disk check

when Windows is not full running, because it needs exclusive access to the Hard Disk been checked, blah blah blah)

i. then Left Click the “Start” Button in the corner of your screen

j. Left Click “Turn off Computer…”

k. Left Click on “Restart”

As your computer re-starts, before starting full Windows Xp

a blue screen should appear, giving a Ten (10) second countdown

please don’t press any keys at this stage,

wait for the Hard Disk check to begin

(then go make a tea or something,
average checking times for a 20Gb Hard Disk: 15 – 80 mins)

Once the Hard Disk check has finished the computer may:
a) Re-boot / re-start then load Windows
b) immediately load Windows

Both these are normal, any errors should have been repaired,
unless serious errors have occurred on your Hard Disk Drive,in that case, back-up your personal data (photos, favorites, etc),
to CD / DVD or Removable Storage Device and have the Hard Disk Drive replaced by qualified service personnel as soon as possible. ;0)

Kind Regards

Bob