Hi,
Please clarify,
How do you connect to the Internet (DSL, Dialup, cable)?
Did you experience any spyware alert or advertisement in the computer?
What is the memory size of the computer (RAM)? (Start-Right click on my computer Icon-properties)?
Steps:
Try to boot the Vista computer in the Safe mode with networking.(Restart the computer - tap the F8 Key in the key board – select the Safe mode or last known good configuration from the Advance boot-up option)
Try to perform the clean boot in the XP machine. (Start-Run-Msconfig-startup tab-disable all)
Perform the McAfee Virtual Technician in both computer and post the session ID
http://mvt.mcafee.com/mvt/default.asp