do i need to delete my old anti virus programs before installing the new one?

you should be running only one resident anti-virus program at any given time.

 

here's the best way to change:

 

make sure you already have the installation file for the new/desired anti-virus program (either in terms of it being on a CD, or having already downloaded it to your computer).  

 

then disconnect yourself from the internet (e.g., by unplugging your Ethernet cable, or turning your router off, or disabling your wireless card).

 

use add/remove programs to REMOVE your old/UNdesired anti-virus program

 

and finally, run the installation file to install your new/desired anti-virus.

 

after the installation is successfully completed, you can reconnect yourself to the internet, then allow the anti-virus to obtain its most recent updates.   at this point, if you wish, you can scan your system for viruses.

Just to add to what ky331 has mentioned, some anti-virus vendors provide free removal tools to be used after Add/Remove Programs. These follow-ups will remove any remnants. What particular AV are you planning to remove?

Thanks a lot guys for the help so far. Just to let you guys know...my laptop came with Norton Antivirus but it expired about a year ago. for a while i was able to run the update but not anymore. then i installed another form of norton scan. Someone also recommended another program called windows defender. So to sum it all up...i have 3 AV programs. So far they are not causing any problems.....unless these problems are so small that i didnt even notice. I want to just remove all of these and install the new AVG 8.0 free edition but i wasnt sure if i should delete these ones or not. So if you guys recommend that i remove all the previous programs and install this then i will. but im all ears for any more advice. again..thanks so far.

Windows Defender is an anti-SPYWARE program, not an anti-virus:

 

"Windows Defender... helps you stay productive by protecting your computer against pop-ups, slow performance and security threats caused by spyware and other potentially unwanted software."

 

as for your other "form of Norton scan", that could be anti-virus, or anti-spyware, or anti-rootkit, or...

 

avg 8.0 includes both anti-virus as well as anti-spyware protection.   by all means, remove your old [expired!!] Norton anti-virus.  

as for the other norton "scan", it depends on whether it's strictly an "on-demand" scanner ONLY, or if it also has a resident module [and in the latter case, what type of resident protection it offers].  

finally, I'd say you should leave windows defender alone, unless you notice any slowdowns/conflicts with avg's anti-SPYWARE components.

It is not a good idea to run two antivirus programs on your computer at the same time. Can you tell us which program you are currently running?AVG NORTON MCAFEE or AVAST etc..... By running two of them, it may cause a crash on your computer.

First, i would recommend you to make the clean uninstallation via add/remove program or download the norton removal tool.

Second, window defender is the anti-spyware. So far, it doesnt has any problem to run with other antivirus or spyware. As earlier post said, you may leave this program to run if you never expereince of slowdown in the performance from your computer.

 

I would recommend you to run a single antivirus software.....

 

After you have removed NAV using Add/Remove Programs it might be good to use the tool from Symantec to completely remove your Symantec products. It is available here: http://service1.symantec.com/SUPPORT/tsgeninfo.nsf/docid/2005033108162039

As ky331 mentioned, leave Windows Defender alone. Most users have no problem running AVG and Windows Defender on the same system.