simple soln okay here goes
1. get antivir/avg free editions. antivir is slightly better in performance(scanning etc). but if u use outlook/thunderbird then u will need e mail scanning too . that is not available in antivir , for that goto avg free.
also antivir will give those annoying pop ups after successful update.
2. get a free firewall. can gofor pc tools,zone alarm etc etc.i would recommend u comodo firewall for best windows protection but it not for newbies.
3. get a signature based antispyware . it will reside in memory (like anvirus) and regularly update itself. i recommend u spyware terminator.
4. get a rule based antispyware(hips). like threatfire etc . also it can be enable explicitly on spyware terminator , comodo (that way u don't have to install one more software) it will bombard u with permissions /questions but soon they will reduce as the permissions are learned.
i would personally recommend u to get ubuntu and forget all of the above.
if u cant do that then get antivir+comodo(with defence+ enabled).let me warn u that comodo is not for noobs . but i used it and i can offer most rock solid protection u can get in windows , even better than commercial applications.
it is the closest u can get to linux like safety in windows IMHO.
good luck