If you are using Windows 98...
...you can manually go extra deep into your registry and inactivate a file named INDEX.DAT. As I remember, registry cleaners will not find this file, it's probably part of the operating system, so it's up up you to find this file using D.O.S. ("Disk Operating System") and rename or delete this file (or change it's contents). When you read that file (using the TYPE command), you will see the REDIRECT commands of the rogue (spyware, p 0 r n, etc.) websites.
You first have to RESTART IN DOS MODE. As I remember, the command prompt in DOS will then say...
C:\>windows (capital letters are unecessary in DOS).
In order to get to the main directory (so it doesn't say "Windows"), press CD (and then press enter).
The command to search the whole hard drive for INDEX.DAT and put the search results into a file named ROGUE is...
C:\>dir index.dat /s >rogue (and then press enter)
The search might take 2 to 5 minutes. When it is finished, the command prompt will be...
C:/>
Then put...
C:/>type rogue | more (that PIPE command before "more" is not a vertical line, it is the uppercase symbol of the FORWARD SLASH KEY) and press enter. The PIPE command will allow you to read the file one page at a time (pressing enter to see "MORE".
Now that you can read the file named ROGUE, you will probably see many instances of
the file "index.dat". The offending instance of index.dat is in the Windows Cookie directory. To get into the "Windows" subdirectory, press CD windows (and press enter).
From there, to get to the COOKIES directory, press CD cookies (and press enter).
To be able to read index.dat, press TYPE index.dat (and press enter) OR use the EDIT program. The command is...
EDIT index.dat (and press enter), this is easier because it has it's own menu.
It's safer not to ever delete a file, but it doesn't matter if you delete index.dat because it always rebuilds itself, but after you read index.dat (uneccesary but interesting), you can change the contents with the BACKSPACE key or you can rename the file to compare how the file will rebuild itself next time you start the computer.
As I remember, 98 was the last O.S. to use COMPLETE DOS (with XP and Vista you cannot do this).
Also check your TASK LIST (pressing CTRL-ALT-DEL once) and see what processes are running on your computer without you knowing.
Go to
http://www.answersthatwork.com
to find out what those processes do (free task list dictionary, very good).
In order to exit DOS and return to WINDOWS, the command is...
C:\>exit (and press enter).