Problem with XP Pro after auto reboot

Good evening folks, I have need of your services once again. Running a Dell Dimension 3100c with XP Pro. Working just fine. Left machine to get a coffee and when returned was in final sequence of shutdown. Machine rebooted and I immediately noticed a change in appearance of the taskbar at bottom of desktop. Now in plain white. There is no internet connection. Tried to access Win firewall and get message "..cannot be displayed because the associated service is not running".

I am using a laptop to send you this post and am sat beside sick Dell. Look forward to your suggestions.

Kind regards.

Addition to the above post, my son runs a Dell laptop also with XP and this now has the same symptoms. Sounds like an issue with windows auto update??

Do you have McAfee installed in both the machines ????

Yes. Seems to be called On-Access Scan. Was added when I began working with a new company by an IT person supplied by the new company. The company is in the financial services sector.

I have 2 other machines running Vista, this post is coming from one of them, which had the McAfee On-Access loaded at the same time as the 2 problem machines. Is there anything I could do in order to prevent a similar problem as losing these 2 machines will seriously disrupt business?

Regards.

Cantrad.. The below link is for your Information...

http://www.theregister.co.uk/2010/04/22/mcafee_false_positive_analysis/

Most of the users(Both Home & Corporate users), who had Mcafee DAT Version 5958 got affected by it. It all happened with a Rogue Update by Mcafee.

Mcafee recommends this Solution.

https://kc.mcafee.com/corporate/index?page=content&id=KB68780

I beleive, Computers with McAfee 5959 DAT should be safe..

MetalMusk, good call, both machines back to normal. Many thanks and apologies for delay in responding.
All the best, cheers, Cantrad.