Outlook 2000 SP3 POP3 connect issues

Hello,

WinXP Pro, Outlook 2k SP3 POP3 server connect failures.
a) can send/receive emails under 100kb
b) setup Outlook logging, and see server connect failures
in logs for all email accounts across 3 domains.

Things tried
1) All usual settings checked over, been running smoothly
for months - ZoneAlarm, McAfee v8. Same results whether
these disabled or enabled [did shut them down to test].
2) Removed/Re-added Outlook email accounts. All settings
standard POP3 110. Also tried increasing time-out.
3) Uninstalled/Re-installed Outlook
4) Moved outlook.pst and let Outlook recreate fresh pst.
5) Same issues whether dialup ISP or home cable modem
6) Contacted all domain hosts and dialup ISP support
desk. Sent Outlook logs to domain hosts.
7) Can telnet to POP3 servers - no issue.
8) IE v6 and all webmail runs smoothly.
9) WinXP Pro, ZoneAlarm, McAfee's, Office2k - all MS
updates applied and current.
10) And yes, virus checked twice.

In testing, only small 100kb emails getting thru. Empty
email accounts also erroring out.

POP3 Log has text such as...
POP3: 13:28:53 [db] err: WSAGETSELECTEVENT = 0x10,
WSAGETSELECTERROR = 10049
POP3: 13:28:53 [db] ERROR: "The connection to the server
has failed.", hr=2148322318

Tested on another Windows2000 PC. Outlook 2000 works
fine there. i.e. can pull down a larger (1.5mb) email on
a problem email account.

Back to problem PC: WinXP Outlook tries to send error
log to MS regarding an abort in shlwapi.dll [have
allowed to send once]

How did I get here? I think while I was trying to defrag
(done many times before) I let my notebook lose battery
power. Is MS defrag not robust enough to handle mid
process shutdown?

I am beginning to think I have corrupted my WinXP dll's
1) Any thoughts?

2) What is best way to fix corrrupt dll's without
formatting and reloading [I have alot on my PC].

3) Will a reload of WinXP Pro (full version) replace the
system dll's??? I see various website suggestions for
replacing shell32 and shlwapi - using batch DOS commands
and Recovery Console. Don't want to make myself a bigger
mess.

Appreciate any and all help.
Sme