1. IF using McAffee firewall then turn XP firewall off. Two firewalls will result in less security not more & result in side effects due to clashes also.
2. RAM is random access memory. It's how much memory your computer can store temporarily in the RAM processor units.
3. Modem & Router .. check the wires leading from your computer. One will lead to a box that is a modem or router & on it will say the brand name & a model number. Modems are how you connect to the internet.

Most routers & some modems use NAT which behaves similar to a firewall.

So depending on which brand & model you have it may be part of the problem.