I had the antivirusxp virus on my computer and went through the regestry and got rid of everything I could find. rhcn4wj0er6g was associated with the virus. Now I have found shcl4wj0er6g in my regestry. Has anyone herd of this and could it be part of a virus? Ever since I got rid of the antivirusxp I am unable to switch between users, any ideas? Any help is appreciated.

Have you gone through the following steps?

To turn Fast User Switching on or off
You must have a computer administrator account to turn on or off the Use Fast User Switching feature.

Open User Accounts in Control Panel.
Under Pick a task, click Change the way users log on or off.
Do one of the following:
To specify that a user's programs remain running when another user logs on to the computer, select the Use Fast User Switching check box.
If you select this option, programs do not shut down when another user logs on to the computer. For example, if you are typing a report and your child wants to check e-mail, you can log off using Switch User, the child can log on, check e-mail, and then log off. You can log on and return to your report without losing your place.

To specify that programs shut down when users log off the computer, clear the Use Fast User Switching check box.
If you select this option, programs automatically shut down when users log off the computer, and the computer will run faster for the next user who logs on.

Important

When Fast User Switching is turned on, Serial Keys will not work. Serial Keys is an accessibility feature that provides support so that alternative input devices (such as single switch or puff and sip devices) can be used in place of the computer's standard keyboard or mouse.
Notes

To open User Accounts, click Start, click Control Panel, and then click User Accounts.
Fast User Switching cannot be turned off while multiple users are logged on to the computer.

If so, post back where it "fails" in the above steps.