internet security is not enough for pc protection

never depend on any antivirus / internet secuity for your protection from viruses

always have an alternate for the future

for example fake-antivirus/programs (example : antivitus 2009/2010 or windows dsik defragmenter ) disables the main antivirus / internet security

so use some other applications also which are not affcted by by the fakeviruses / programs 

and which have portability also like

1. kaspersky virus removal tool works better than antiviruses

2. RRT sergiwa antiviral toolkit helps for normal functioning of the windows (because after removing the viruses its after effects always interrupts the computer users due to the changes in registries )  . it works fast

3. USB disk security (optional if RRT is not availible )

these programs are not affected by any fake-virus or similar programs