I suggest dump W98 and put W2k or WinXP on that if you wish to use Windows.
-edit-
For antivirus you can use AntiVir or AVG. WinXP has an inbuilt firewall (opinions vary on it though).
Here's a list of other firewalls.
For spyware I can think of Ad-Aware and Spyblaster from the top of my head.
