Here's what I got from my PC manufacturer's support. I'm not sure if I will do this right away because I am away from home and I don't want to cause additional problems with my computer.
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We suggest you perform the System Restore procedure for Windows XP to
resolve the issue.
IMPORTANT: System Restore will restore the Windows Registry and other
settings back to the date and time selected. Saved e-mail
will not be affected, but you will need to reinstall any
hardware or software installed after the date of the restore
point used.
IMPORTANT: You may experience data file loss during the Restore process
on any data files not stored in the "My Documents" folder.
You should backup or copy any data files to the either the
My Documents folder, or removable media (e.g. Floppy, CD-R)
to avoid losing data before performing the restore.
NOTE: If the system will not start Windows in normal mode, the System
Restore feature can be run from inside Safe Mode.
1. Click Start
2. Point to All Programs
3. Point to Accessories
4. Point to System Tools
5. Click System Restore
NOTE: If System Restore is not listed in the System Tools menu,
click the Start button and then click Help and Support.
Under Pick a task, click System Restore.
6. In the System Restore window, click Next
NOTE: If a second user is logged on as a different user, you may
receive a warning. Click OK to continue.
7. Under 1. On this calendar..., click the left arrow (<) or right
arrow (>) buttons to select a month.
(Choose a date prior to when you started experiencing this issue)
8. Under 2. On this list..., click the left arrow (<) or right arrow
(>) buttons to select a day and then click the restore point time.
NOTE: If no days are displayed verify System Restore is enabled.
a. Click the Start button and then click the Control Panel.
b. In the Control Panel window, click Performance and
Maintenance.
c. In the Performance and Maintenance window, click
Administrative Tools.
d. In the Administrative Tools window, click the Computer
Management icon.
e. In the Computer Management window, double-click Services
and Applications.
f. Double-click Services.
g. In the Services window, double-click System Restore
Services.
h. In the System Restore Service Properties (Local Computer)
window, locate Service Status.
NOTE: If System Restore is operating, Started will be
shown. If System Restore is not operating, Stopped
will be shown.
9. Click Next
10. Click Next to confirm the restore point
NOTE: The system will be restored to the date and time selected and
then automatically restart. At the Windows XP Welcome screen,
click the desired user name or icon to log in.