WinXP machine cannot VPN (with Microsoft VPN client) to any network

I have XP Pro running on a Lenovo Thinkpad T60.  For 2 years, I've never had a problem with VPN.  I regularly connect to 6 or 7 different VPN sites, which all use different logon info/domains.  

Recently (about 2 months ago) it stopped being able to make VPN connections.  It's running the same version of WinXP Pro, with the same service pack, and all of the same updates, and the same version of virus scanner as other machines in my office.   And this is the only machine that has the problem.

All other network functionality works fine except VPN.

When I try to VPN, I get up though the registration step, and then I get
Error 720: Connection to the remote computer could not be established. You might need to change the network settings for this connection.

I've tried matching all VPN settings with a computer that will successfully connect (authentication, encryption, etc)
I've rebuilt the VPN connection.
I've turned off the firewall.
I've updated the network drivers.
I've uninstalled/rebooted/reinstalled the network driver.
I've updated windows
I've checked the symantec logs to make sure it didn't quarantine any files.

What else could be failing that would not allow my VPN to connect?

Thanks in advance for the help.

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Raymond JansenCommented:
I might be way of, but did you have Symantec Endpoint protection installed and later removed this? If yes, check the following link:

It sounds like a corrupted system file or winsock issue.

To repair winsock run;
netsh winsock reset

To repair corrupted system files;
With your XP Pro CD in the computer run the following command from a command prompt
sfc /scannow
TomProAuthor Commented:
R - We've never installed symantec endpoint, but I deleted the reg entries anyway, and still no dice.
Ten - No dice on either of your solutions either.

Other suggestions?
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There might be some type of conflict.  Use msconfig to stop all non-Microsoft services and all startup programs and then retest.  

If that doesn't work try doing a repair from the installation CD.
TomProAuthor Commented:
Turned off all non-microsoft services with msconfig:  VPN still fails.

Then I did a repair with from Windows Installation CD, and it has done something terrible:
Boot from XP Pro CD
Run repair on OS
Files are copied.
Displays message that computer will be rebooted.
Computer shuts down.
Computer starts
Bios runs fine, including full memory check, everything fine.
Windows Splash screen (with scrolling bar below it) shows up, and bar scrolls approximately twice and normal speed.
THEN bar slows to a crawl.
Single blocks are drawn and erased at a time, so I can watch it slowly progress across screen.
Appears like computer is VERY busy doing some work.
Consistent but infrequent access of disk.

Bar progresses across screen approximately 40 to 50 times, over the course of 25 minutes.
Then screen goes black for 4-5 minutes.
Then screen SLOWLY starts to paint blue background of standard login screen.
(IT's apparently TRYING to boot)
As soon as whole screen is painted blue screen of death.

I've double checked that the disk is readable, and that the memory is fine.
Your suggestion now?

TomProAuthor Commented:
Oh, I forgot to mention: after turning everything off in msconfig, and vpn failing, I set it back to standard boot with all normal services, and rebooted twice to make sure it was back to normal (which it was), BEFORE I ran the WinXP repair.
TomProAuthor Commented:
Raising points to 500, because I NEED this computer back up before the weekend (taking it on an international business trip)
I am so sorry this happened.

Do you have what the blue screen error is?  If the computer is rebooting before you can see the message then hit F8 and choose the option disable automatic restart on system failure.  And post the blue screen error message that you're getting.

I would unplug any extra devices you have plugged into the computer and try to boot again.  If it's still blue screening hit F8 and try safe mode.

If safe mode isn't working then boot off the CD again and go into repair mode and run chkdsk /r to fix any hard drive issues.

Good luck.

Also to increase visibility you could post another question and put a link to this one and promise double points (1000) for anyone with a solution to your boot up problem.
TomProAuthor Commented:
The blue screen is a corrupt boot sector error.

I don't have any devices plugged in, I'd removed everything before I did the windows repair.

Safe mode didn't work either.

I'm running checkdisk now.

Opening a second link sounds like cheating, but if this chkdsk doesn't work, I might be forced to do so.
I think I can justify it because there's 2 seperate problems here (VPN is one, and now blue screen is second)
After you finish checkdisk then run fixboot and fixmbr while you're still in the repair mode.  This can fix common issues with your booting up and your Master boot record.
TomProAuthor Commented:
Will do.
It's been running for over an hour and a half, and is only 51% done.
So I'm heading home for the night.

I'll run the fixboot and fixmbr tomorrow morning and let you know what I find.
TomProAuthor Commented:
No luck on the fixmbr and fixboot.

Generally when I see a mbr problem, I'd have expected it to bluescreen right away.
the fact that it runs the windows splash screen for 30 minutes first makes me think that it's not still an mbr problem.
But that's just me.
I know the data on the disk is still good...and it's trying to boot to windows so it's not like it's a partition problem.
What's next?
TomProAuthor Commented:

Did the fixmbr and fixboot again...but this time did them in the reverse order (fixmbr first, fixboot second).

Still no luck.
But then I took out the WinXP Pro CD again, and slipstreamed SP3 onto it.
Did the automated repair again, and this time the repair cycle went all the way thru, and I got my system back on it's feet.

Unfortunately, we're now back to problem #1: VPN still doesn't work.

So what's next?
And hopefully it doesn't require doing a windows repair.  :)

I was just suggesting to retry the repair when I saw I had a new email... Glad to see we're at least back to the start point.

Now that you ran the repair, retry the troubleshooting steps that you mentioned in your opening post.

Also review the event logs for any problems.

TomProAuthor Commented:
I ran all updates that I knew how to do.
I ran all fixes that I'd tested last time, and I had no luck.
Ended up reinstalling SP3 again, as well.

All with no luck.

As a result, I kept the computer running long enough to buy another disk and restage the whole machine.
Remarkably - VPN works on that one.

Thanks for the help, Tenaj.
I'll split off some of the points for at least helping me out of the jam when I couldn't get the system to boot at all.

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Glad to hear you're back up and running :).  Thanks for the points.
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