How to clean a computer with multiple accounts infected with spyware, viruses? [duplicate]

Possible Duplicate:
What to do if my computer is infected by a virus or a malware?

What's the best way to clean a computer with multiple accounts infected with spyware, viruses and malware? Should you install and run software to remove the infections on each account? If you install the software on one account, will it clean the entire computer including each account?

For example, some programs like CCleaner will install only on one account and not offer the option for all users (accounts). Does this mean the program will clean the entire computer including other accounts or do I have to install CCleaner on each account to clean up each user's account?

Solution 1:

The best way would be to wipe the harddrive and then reinstall everything, reinstalling the anti-virus program first, then anti-spyware. This will fix all the accounts.

The details for whether a malware removal tool will affect all accounts or just one is dependent on that particular tool. However, wiping the harddrive will guaruntee every trace is gone (usually). Malware removal tools may leave pieces of malware scattered about.

Solution 2:

I usually use malware bytes to remove stubborn viruses. Most of the time it is much better to just nuke the hard drive and freshly install the operating system. A deep rooted virus can take vital system files with it whenever you try to remove the virus. This can cause instability and cause a lot of system errors. If you do decide to use a removal approach instead of a reformat, make sure that you use 2 or 3 well known virus removers since not every kind will catch every strand of virus.

Solution 3:

You also should boot up the computer in safe mode, because anti-spyware/virus software may not be able remove infected files in normal mode.