I tried the Malwarebytes first - it found some viruses, but the same annoyances are still happening.

And now I’m getting another error message that persistantly won’t go away:

“Just-In-Time Debugging
An exception 'Runtime Error has occured in Script.
However, no debuggers are registered that can debug this exception. Unable to JIT debug.”

(Malwarebytes log):

Malwarebytes’ Anti-Malware 1.50.1.1100
www.malwarebytes.org

Database version: 6526

Windows 5.1.2600 Service Pack 3
Internet Explorer 7.0.5730.13

05/07/2011 2:06:43 PM
mbam-log-2011-05-07 (14-06-43).txt

Scan type: Full scan (C:|)
Objects scanned: 282247
Time elapsed: 1 hour(s), 15 minute(s), 17 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 3
Registry Values Infected: 1
Registry Data Items Infected: 1
Folders Infected: 0
Files Infected: 1

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Ext\Settings{100EB1FD-D03E-47FD-81F3-EE91287F9465} (Adware.ShopperReports) → Quarantined and deleted successfully.
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Ext\Stats{E8BDFF85-F8C2-4281-8669-31253E646518} (Adware.Hotbar) → Quarantined and deleted successfully.
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\ (Hijack.Zones) → Quarantined and deleted successfully.

Registry Values Infected:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Nbegisurasew (IPH.Trojan.Hiloti.B) → Value: Nbegisurasew → Quarantined and deleted successfully.

Registry Data Items Infected:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Start_ShowHelp (PUM.Hijack.StartMenu) → Bad: (0) Good: (1) → Quarantined and deleted successfully.

Folders Infected:
(No malicious items detected)

Files Infected:
c:\WINDOWS\owoburuy.dll (IPH.Trojan.Hiloti.B) → Quarantined and deleted successfully.