hi! pls how many firewalls can one have on ones pc.

Well, technically you could have loads, but the amount we recommend is just one, to stop them conflicting with each other.

The same goes to having more than one A.V. software . They will conflict .

Hello king gee, please take a moment and read this informative BC Tutorial
Understanding and Using Firewalls

Yes it is considered propoer proceedure to only have ONE software firewall active at a time. If you use a router (which is in reality a hardware Firewall) it is still advised to have one software firewall. I would also recommend you use one other than the Windows Firewall as that only monitors Inbound traffic.

If necessary see the Firewalls section here
Freeware Replacements For Common Commercial Apps

I think one...but if u have many they will conflict or something...same as antiviruses...

It was prior to the Microsoft Security Initiative of August 2004,which provided for the Security Center download and update commonly referred to as SP2 that Microsofts firewall was present in Windows but whose attributes had to be enabled by your own ability and was not enabled as a matter of right.This was a limited presence and was even more restrictive than merely requiring an ability that needed knowledge a forethought to enable.It was not enabled at Boot Sequence irregardless which allowed interests to infiltrate if so desired.That is you could design work arounds to off set any advantage a firewall could provide.Though this was an often cited example of how it is done it was not so easy as this suggests because the firewall was quite capable.The SP1 firewall is what this would qualify as.It was during this time period roughly 2001 through 2004 that the ability to utilize two firewalls on the same computer became a relative possibility and indeed there was even some personal experience with my own computer whereby two firewalls could be run or at least possess the appearance of being enabled at the same time that that kind of thinking made its presence known.At present that is no longer a desired nor possible configuration as to a Personal Computer.If there was to be an attempt to allow for a second firewall simultaneously while all the while another was enabled there would be a conflict of interest with the event occurring providing for an exploit whereby a exploit could actually come in under the radar so to speak and as a result exploit a conflict that the presence of two firewalls enabled simultaneously would provide.I do not think that the Security Center would allow for the Conflict of Interest and as a result would allow the computer user to be advised while Microsoft because of the SP2 Security Initiative of 2004 designed the initiative to default to one or the other with at least the presence of at least one firewall and for that matter one anti-virus with no more than one but at least one so to always provide a secured ability as to the computers working environment.Rule of thumb says no more than one firewall

Using two software firewalls on a single computer could cause issues with connectivity to the Internet or other unexpected behavior. Further, running multiple software firewalls can cause conflicts. Only one of the firewalls can receive the packets over the network and process them. Sometimes you may even have a conflict that causes neither firewall to protect your connection. However, you can use a hardware firewall (your router) and a software firewall (Kerio or ZoneAlarm) in conjunction.

A hardware firewall is really a software firewall running on a dedicated piece of hardware or specialized device (routers, broadband gateways) that sits between a modem and a computer or network. A hardware firewall is based on "Network Address Translation" (NAT) which hides your computer from the Internet or NAT plus "Stateful Packet Inspection" (SPI). It can provide a strong degree of protection from most forms of attacks coming from the outside (incoming traffic). Hardware firewalls are easy to configure and can protect every machine on a local or home network. A hardware firewall typically uses packet filtering to examine the header of a packet to determine its source and destination addresses. This information is compared to a set of predefined or user-created rules that determine whether the packet is allowed (forwarded) or denied (dropped) on particular ports. They tend to treat any kind of traffic traveling from the local network out to the Internet as safe which can be a security risk.

With a software firewall you have customized control and can specify which applications are allowed to communicate (outgoing traffic) over the Internet from your computer. Programs that are not explicitly allowed to do so are either blocked or else the user is prompted for confirmation before the traffic is allowed to pass. Software firewalls generally offer the best measure of protection against Trojans and worms but they are harder to configure and must share resources with other running processes which can decrease system performance. Many software firewalls have user defined controls for setting up safe file and printer sharing and to block unsafe applications from running on your system.