My computer is all better now. Yesterday, about mid-morning, it became infected with a virus. Finally, about midnight, all was restored and fine again. What a day! Fourteen hours on a repair job.
I picked it up the virus (worm.W32.NetSky) when I opened an image off Google Images. I was looking for some wallpaper. Suddenly, I began getting infected messages from McAfee and Windows and my browser would not respond or open and I couldn't get on-line anymore. I checked to make sure McAfee (my anti-virus software) was up to date and then I ran a full scan of my hard drive and it found about 30 bad files. That took an hour. I downloaded Spybot and ran it, isolated the bad stuff and cleaned it all off the hard drive. Another hour. Then, after the Spybot automatic shutdown and restart, my log-in prompt went into a loop (I would log-in, hit enter, get two quick windows messages, and then go back to a blank log-in prompt, and repeat, and repeat, with no change) and Windows would not start. "Uh-oh, this is trouble now!"
At this point I started up my laptop computer and went online to find answers in the forums and from Microsoft. More hours. It seems that viruses will change Windows code and Registry code so when the bad files are removed, the good software is changed and doesn't run correctly. I found my boot CD for Windows XP, the key code, my admin password, etc. (that took some time too) and then figured out how to boot from the CD during start-up. Then I used the repair console from the boot CD to fix the code. That didn't work after numerous attempts. More research. Back to the boot CD and this time I did a full repair install (followed instructions from Microsoft). It took two hours but it worked and then I could log in and see everything.....except my screen background had turned an odd green color and I couldn't change it in the Desktop properties dialog box. I also had to go online and get the latest XP patch and security updates downloaded which took an hour. More online research and I found information about the wallpaper control problem from Microsoft. After opening up the Registry, and figuring out how to make changes in the code, I found the one place where the value of "1" should be "0". After that change and a restart, my background color control was restored and I changed the color to a nice blue.
All else seems to work fine now. Needless to say, I learned a lot about computers yesterday. The main thing I learned about on-line browsing: don't click and open anything if you don't have some faith in the source of the item. If it's just out there on-line, it's risky, and the trouble caused can be very frustrating and time-consuming. Even my firewall / virus scan software (McAfee) didn't prevent the infection. Now I have McAfee fully updated and have also enabled the Windows XP firewall.