Free AVG.com is something that you should down load to keep the virus on your computer to a minimum.
Free AVG is good and kept my windows netbook clean right up to the time I powered it off and converted to Ubuntu Linux.
Ubuntu comes with email programs that will work with any POP3 email, Gmail, and has Firefox built in, you can install Chrome, and comes with Open Office 3.2 that will work with any MS Office 2010 file
IM is done through Pidgin which is easy enough to set up ..... and with all the themes out there you can make it look 95% like XP
Virus and pop ups do not work on Linux as they are not written for the workstation, but for the server....
Now for the GOOD thing.. Ubuntu upon install CAN encrypt your HD so your stuff has a layer of protection. Also the permissions are better.